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[MCQ’s] Computer Organization and Architecture

Module 1

1. Any signed negative binary number is recognised by its ________
a) MSB
b) LSB
c) Byte
d) Nibble
Answer: a
Explanation: Any negative number is recognized by its MSB (Most Significant Bit).
If it’s 1, then ít’s negative, else if it’s 0, then positive.

2. The parameter through which 16 distinct values can be represented is known as ________
a) Bit
b) Byte
c) Word
d) Nibble
Answer: c
Explanation: It can be represented up to 16 different values with the help of a Word. Nibble is a combination of four bits and Byte is a combination of 8 bits. It is “word” that is said to be a collection of 16-bits on most of the systems.

3. If the decimal number is a fraction then its binary equivalent is obtained by ________ the number continuously by 2.
a) Dividing
b) Multiplying
c) Adding
d) Subtracting
Answer: b
Explanation: On multiplying the decimal number continuously by 2, the binary equivalent is obtained by the collection of the integer part. However, if it’s an integer, then it’s binary equivalent is determined by dividing the number by 2 and collecting the remainders.

4. The representation of octal number (532.2)8 in decimal is ________
a) (346.25)10
b) (532.864)10
c) (340.67)10
d) (531.668)10
Answer: a
Explanation: Octal to Decimal conversion is obtained by multiplying 8 to the power of base index along with the value at that index position.
(532.2)8 = 5 * 82 + 3 * 81 + 2 * 80 + 2 * 8-1 = (346.25)10

5. The decimal equivalent of the binary number (1011.011)2 is ________
a) (11.375)10
b) (10.123)10
c) (11.175)10
d) (9.23)10
Answer: a
Explanation: Binary to Decimal conversion is obtained by multiplying 2 to the power of base index along with the value at that index position.
1 * 23 + 0 * 22 + 1 * 21 +1*20 + 0 * 2-1 +1 * 2-2 + 1 * 2-3 = (11.375)10
Hence, (1011.011)2 = (11.375)10

6. An important drawback of binary system is ________
a) It requires very large string of 1’s and 0’s to represent a decimal number
b) It requires sparingly small string of 1’s and 0’s to represent a decimal number
c) It requires large string of 1’s and small string of 0’s to represent a decimal number
d) It requires small string of 1’s and large string of 0’s to represent a decimal number
Answer: a
Explanation: The most vital drawback of binary system is that it requires very large string of 1’s and 0’s to represent a decimal number. Hence, Hexadecimal systems are used by processors for calculation purposes as it compresses the long binary strings into small parts.

7. The decimal equivalent of the octal number (645)8 is ______
a) (450)10
b) (451)10
c) (421)10
d) (501)10
Answer: c
Explanation: Octal to Decimal conversion is obtained by multiplying 8 to the power of base index along with the value at that index position.
The decimal equivalent of the octal number (645)8 is 6 * 82 + 4 * 81 + 5 * 80 = 6 * 64 + 4 * 8 + 5 = 384 + 32 + 5 = (421)10.

8. The largest two digit hexadecimal number is ________
a) (FE)16
b) (FD)16
c) (FF)16
d) (EF)16
Answer: c
Explanation: (FE)16 is 254 in decimal system, while (FD)16 is 253. (EF)16 is 239 in decimal system. And, (FF)16 is 255. Thus, The largest two-digit hexadecimal number is (FF)16.

9. Representation of hexadecimal number (6DE)H in decimal:
a) 6 * 162 + 13 * 161 + 14 * 160
b) 6 * 162 + 12 * 161 + 13 * 160
c) 6 * 162 + 11 * 161 + 14 * 160
d) 6 * 162 + 14 * 161 + 15 * 160
Answer: a
Explanation: Hexadecimal to Decimal conversion is obtained by multiplying 16 to the power of base index along with the value at that index position.
In hexadecimal number D & E represents 13 & 14 respectively.
So, 6DE = 6 * 162 + 13 * 161 + 14 * 160.

10. The quantity of double word is ________
a) 16 bits
b) 32 bits
c) 4 bits
d) 8 bits
Answer: b
Explanation: One word means 16 bits, Thus, the quantity of double word is 32 bits.
Sanfoundry Global Education & Learning Series – Digital Circuits.

11. 1’s complement of 1011101 is ____________
a) 0101110
b) 1001101
c) 0100010
d) 1100101
Answer: c
Explanation: 1’s complement of a binary number is obtained by reversing the binary bits. All the 1’s to 0’s and 0’s to 1’s.

12. 2’s complement of 11001011 is ____________
a) 01010111
b) 11010100
c) 00110101
d) 11100010
Answer: c
Explanation: 2’s complement of a binary number is obtained by finding the 1’s complement of the number and then adding 1 to it.
2’s complement of 11001011 = 00110100 + 1 = 00110101.

13. On subtracting (01010)2 from (11110)2 using 1’s complement, we get ____________
a) 01001
b) 11010
c) 10101
d) 10100
Answer: d
Explanation: Steps For Subtraction using 1’s complement are:
-> 1’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and 1 is added to the last bit of the result.
-> Else, if there is no carry, then 1’s complement of the result is found out and a ‘-’ sign preceeds the result.

14. On subtracting (010110)2 from (1011001)2 using 2’s complement, we get ____________
a) 0111001
b) 1100101
c) 0110110
d) 1000011
Answer: d
Explanation: Steps For Subtraction using 2’s complement are:
-> 2’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and the result is positive.
-> Else, if there is no carry, then 2’s complement of the result is found out and a ‘-’ sign preceeds the result.

15. On subtracting (001100)2 from (101001)2 using 2’s complement, we get ____________
a) 1101100
b) 011101
c) 11010101
d) 11010111
Answer: b
Explanation: Steps For Subtraction using 2’s complement are:
-> 2’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and the result is positive.
-> Else, if there is no carry, then 2’s complement of the result is found out and a ‘-’ sign preceeds the result.

16. On addition of 28 and 18 using 2’s complement, we get ____________
a) 00101110
b) 0101110
c) 00101111
d) 1001111
Answer: b
Explanation: Steps for Binary Addition Using 2’s complement:
-> The binary equivalent of the two numbers are obtained and added using the rules of binary addition.

17. On addition of +38 and -20 using 2’s complement, we get ____________
a) 11110001
b) 100001110
c) 010010
d) 110101011
Answer: c
Explanation: Steps for Binary Addition Using 2’s complement:
-> The 2’s complement of the addend is found out and added to the first number.
-> The result is the 2’s complement of the sum obtained.

18. On addition of -46 and +28 using 2’s complement, we get ____________
a) -10010
b) -00101
c) 01011
d) 0100101
Answer: a
Explanation: The BCD form is written of the two given numbers, in their signed form. After which, normal binary addition is performed.
Augend is 28 and Subtrahend is -46.

19. On addition of -33 and -40 using 2’s complement, we get ____________
a) 1001110
b) -110101
c) 0110001
d) -1001001
Answer: d
Explanation: The BCD form is written of the two given numbers, in their signed form. After which, normal binary addition is performed.
Augend is -40 and Subtrahend is -33.

20. On subtracting +28 from +29 using 2’s complement, we get ____________
a) 11111010
b) 111111001
c) 100001
d) 1
Answer: d
Explanation: Steps For Subtraction using 2’s complement are:
-> 2’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and the result is positive.
-> Else, if there is no carry, then 2’s complement of the result is found out and a ‘-’ sign preceeds the result.

21. 1’s complement of 1011101 is ____________
a) 0101110
b) 1001101
c) 0100010
d) 1100101
Answer: c
Explanation: 1’s complement of a binary number is obtained by reversing the binary bits. All the 1’s to 0’s and 0’s to 1’s.

22. 2’s complement of 11001011 is ____________
a) 01010111
b) 11010100
c) 00110101
d) 11100010
Answer: c
Explanation: 2’s complement of a binary number is obtained by finding the 1’s complement of the number and then adding 1 to it.
2’s complement of 11001011 = 00110100 + 1 = 00110101.

23. On subtracting (01010)2 from (11110)2 using 1’s complement, we get ____________
a) 01001
b) 11010
c) 10101
d) 10100
Answer: d
Explanation: Steps For Subtraction using 1’s complement are:
-> 1’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and 1 is added to the last bit of the result.
-> Else, if there is no carry, then 1’s complement of the result is found out and a ‘-’ sign preceeds the result.

24. On subtracting (010110)2 from (1011001)2 using 2’s complement, we get ____________
a) 0111001
b) 1100101
c) 0110110
d) 1000011
Answer: d
Explanation: Steps For Subtraction using 2’s complement are:
-> 2’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and the result is positive.
-> Else, if there is no carry, then 2’s complement of the result is found out and a ‘-’ sign preceeds the result.

25. On subtracting (001100)2 from (101001)2 using 2’s complement, we get ____________
a) 1101100
b) 011101
c) 11010101
d) 11010111
Answer: b
Explanation: Steps For Subtraction using 2’s complement are:
-> 2’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and the result is positive.
-> Else, if there is no carry, then 2’s complement of the result is found out and a ‘-’ sign preceeds the result.

26. On addition of 28 and 18 using 2’s complement, we get ____________
a) 00101110
b) 0101110
c) 00101111
d) 1001111
Answer: b
Explanation: Steps for Binary Addition Using 2’s complement:
-> The binary equivalent of the two numbers are obtained and added using the rules of binary addition.

27. On addition of +38 and -20 using 2’s complement, we get ____________
a) 11110001
b) 100001110
c) 010010
d) 110101011
Answer: c
Explanation: Steps for Binary Addition Using 2’s complement:
-> The 2’s complement of the addend is found out and added to the first number.
-> The result is the 2’s complement of the sum obtained.

28. On addition of -46 and +28 using 2’s complement, we get ____________
a) -10010
b) -00101
c) 01011
d) 0100101
Answer: a
Explanation: The BCD form is written of the two given numbers, in their signed form. After which, normal binary addition is performed.
Augend is 28 and Subtrahend is -46.

29. On addition of -33 and -40 using 2’s complement, we get ____________
a) 1001110
b) -110101
c) 0110001
d) -1001001
Answer: d
Explanation: The BCD form is written of the two given numbers, in their signed form. After which, normal binary addition is performed.
Augend is -40 and Subtrahend is -33.

30. On subtracting +28 from +29 using 2’s complement, we get ____________
a) 11111010
b) 111111001
c) 100001
d) 1
Answer: d
Explanation: Steps For Subtraction using 2’s complement are:
-> 2’s complement of the subtrahend is determined and added to the minuend.
-> If the result has a carry, then it is dropped and the result is positive.
-> Else, if there is no carry, then 2’s complement of the result is found out and a ‘-’ sign preceeds the result.

31. Which of the following is not a positional number system?
a) Roman Number System
b) Octal Number System
c) Binary Number System
d) Hexadecimal Number System
Answer: a
Explanation: The Roman number system isn’t a positional number system since it uses symbols to represent numbers.
The octal number system uses digits from 0-7, the binary number system uses digits from 0-1 whereas, the hexadecimal number system uses digits from 0-15.

32. The value of radix in binary number system is _____________
a) 2
b) 8
c) 10
d) 1
Answer: a
Explanation: In a binary number system, the value of base or radix is 2. The binary system uses only two digits for the representation of numbers, therefore its base id has chosen to be 2.

33. The binary equivalent of the decimal number 10 is __________
a) 0010
b) 10
c) 1010
d) 010
Answer: c
Explanation: To get the binary equivalent of any number, we need to divide the number by 2 and obtain the remainders as :We then write the remainders in the reverse order as 1010 .

34. A computer language that is written in binary codes only is _____
a) machine language
b) C
c) C#
d) pascal
Answer: a
Explanation: Machine Language is written in binary codes only. It can be easily understood by the computer and is very difficult for us to understand. A machine language, unlike other languages, requires no translators or interpreters.

35. The octal equivalent of 1100101.001010 is ______
a) 624.12
b) 145.12
c) 154.12
d) 145.21
Answer: b
Explanation: The octal equivalent is obtained by grouping the numbers into three, from right to left before decimal and from right to left after the decimal place.
Here, i.e. 145.12 is the octal equivalent of the number.

36. The input hexadecimal representation of 1110 is _______________
a) 0111
b) E
c) 15
d) 14
Answer: b
Explanation: In hexadecimal number system, 1110 = 15, which is represented by the alphabet E.
Some representations are:
A 10
B 11
C 12
D 13
E 14
F 15.

37. A bit in a computer terminology means either 0 or 1.
a) True
b) False
Answer: a
Explanation: A bit stands for a binary digit. A binary digit can have only two digits i.e. 0 or 1. A binary number consisting of n-bits is called an n-bit number.

38. Convert the binary equivalent 10101 to its decimal equivalent.
a) 21
b) 12
c) 22
d) 31
Answer: a
Explanation: To convert a binary number to its decimal equivalent follow these steps :
24 * 1 + 23 * 0 + 22 *1 + 21 * 0 + 20 * 1 = 21.
Therefore, the answer is 21.

39. Which of the following is not a binary number?
a) 1111
b) 101
c) 11E
d) 000
Answer: c
Explanation: A binary number can have only two possible digits, 0 and 1. In the third option, there is an alphabet E present which makes it an invalid binary number. Alphabets are only allowed in the hexadecimal number system.

40. Which of the following is the correct representation of a binary number?
a) (124)2
b) 1110
c) (110)2
d) (000)2
Answer: d
Explanation: The binary numbers should comprise only two digits 0 and 1.
Also, for the base, the value should be 2 and it should be written as a subscript enclosing the entire number. Here, the fourth option gives the correct representation.

41. What could be the maximum value of a single digit in an octal number system?
a) 8
b) 7
c) 6
d) 5
Answer: b
Explanation: The maximum value in any number system is one less than the value of the base. The base in an octal number system is 8, therefore, the maximum value of the single digit is 7. It takes digits from 0 to 7.

42. In a number system, each position of a digit represents a specific power of the base.
a) True
b) False
Answer: a
Explanation: In a number system, every digit is denoted by a specific power of base. Like in an octal system, consider the number 113, it will be represented as :
82 * 1 + 81 * 1 + 80 *3.

43. The maximum number of bits sufficient to represent an octal number in binary is _______
a) 4
b) 3
c) 7
d) 8
Answer: b
Explanation: The octal number system comprises of only 8 digits. Hence, three bits (23 = 8) are sufficient to represent any octal number in the binary format.

44. The binary number 111 in octal format is ________________
a) 6
b) 7
c) 8
d) 5
Answer: b
Explanation: Certain binary to octal representations are :
000=0
001=1
010=2
011=3
100=4
101=5
110=6
111=7.

45. Convert (22)8 into its corresponding decimal number.
a) 28
b) 18
c) 81
d) 82
Answer: b
Explanation: To convert an octal number to decimal number:
81 * 2 + 80 * 2 = 16 + 2 = 18.
Hence, the decimal equivalent is 18.

46. The octal equivalent of the binary number (0010010100)2 is ______________
a) 422
b) 242
c) 224
d) 226
Answer: c
Explanation: To obtain the octal equivalent, we take numbers in groups of 3, from right to left

47. Octal subtraction of (232)8 from (417)8 will give ______________
a) 165
b) 185
c) 815
d) 516
Answer: a
Explanation: Octal subtraction is done as follows:
417
– 232
________
165
The octal subtraction is the same as that of any other number system. The only difference is, like in a decimal number system, we borrow a group of 10, in a binary system we borrow a group of 2, in an octal number system, we borrow in groups of 8.

48. The 1’s complement of 0.101 is _________________
a) 1.010
b) 0.010
c) 0.101
d) 1.101
Answer: a
Explanation: The 1’s complement of a number is obtained by reversing the bits with value 1 to 0 and the bits with value 0 to 1.
Here, 0.101 gets converted to 1.010 in its 1’s complement format.

49. Convert (5401)8 to hexadecimal.
a) A01
b) A02
c) B01
d) C01
Answer: c
Explanation: To convert octal to hexadecimal, we first write binary format of the number and then make groups of 4 bits from right to left. Therefore, the hexadecimal equivalent is (B01)16.

50. Express the decimal format of the signed binary number (10010)2 .
a) 2
b) 12
c) -12
d) -2
Answer: d
Explanation: The first bit is the sign bit whereas the rest of the bits are magnitude bits. So the number is: 0010 = 21 * 1 =2
But, the sign bit is 1, Therefore the answer is : (-2)10.

51. What does the symbol D represent in a hexadecimal number system?
a) 8
b) 16
c) 13
d) 14
Answer: c
Explanation: The symbols A, B, C, D, E and F represent 10, 11, 12, 13, 14 and 15 respectively in a hexadecimal system. This system comprises of 15 numbers in total: digits from 0-9 and symbols from A to F.

52. ABC is a valid hexadecimal number.
a) True
b) False
Answer: a
Explanation: In a hexadecimal number system, alphabets are used for the representation of numbers from 10 to 15. Here, A represents 10, B represents 11 and C represents 12. Therefore, it is a valid hexadecimal number.

53. The maximum number of bits sufficient to represent a hexadecimal number in binary:
a) 4
b) 3
c) 7
d) 8
Answer: a
Explanation: The hexadecimal number system comprises of only 15 symbols: 10 digits and 5 symbols. Hence, three bits (24 = 16) are sufficient to represent any hexadecimal number in the binary format.

54. The binary number 1110 in hexadecimal format is _____________
a) 6
b) E
c) 14
d) 15
Answer: b
Explanation: Certain binary to hexadecimal representations are :
1010=A
1011=B
1100=C
1101=D
1110=E
1111=F.

55. Convert (52)16 into its decimal equivalent.
a) 28
b) 83
c) 80
d) 82
Answer: d
Explanation: To convert a hexadecimal number to decimal number:
161 * 5 + 160 * 2 = 80 + 2 = 82
Hence, the decimal equivalent is 82.

56. The hexadecimal equivalent of the binary number (0010010100)2 is :
a) (0B4)16
b) (0A4)16
c) 224
d) 0114
Answer: a
Explanation: To obtain the octal equivalent, we take numbers in groups of 3, from right to left as :

57. Hexadecimal Addition of (3A5)16 and (1B2)16 will give :
a) 557
b) 185
c) 815
d) 516
Answer: a
Explanation: Octal subtraction is done as follows:
3A5
+ 1B2
________
557
In hexadecimal addition of alphabets, we add the corresponding numbers they represent and then subtract the result from 16, then generate a carry of 1 to the next set of numbers.
Here, 5+2=7
A+B=10+11=21-16=5
3+1+1(carry)=5.

58. The 2’s complement of 10.11 :
a) 10
b) 0.010
c) 01.01
d) 10.01
Answer: a
Explanation: The 1’s complement of a number is obtained by reversing the bits with value 1 to 0 and the bits with value 0 to 1. Here, 10.11 gets converted to 01.00 in its 1’s complement format. Further, to convert 1’s complement into 2’s, we add 1 to the result. Here, 01.00+1=10.00.

59. Convert (6532)8 to hexadecimal.
a) (A01)16
b) (A02)16
c) (D5A)16
d) (C01)16
Answer: c
Explanation: To convert octal to hexadecimal, we first write binary format of the number and then make groups of 4 bits from right to left. Therefore, the hexadecimal equivalent is (D5A)16.

60. What do we call the point(decimal) in any hexadecimal number of the form 111.A3?
a) radix
b) hexadecimal point
c) decimal
d) octal point
Answer: b
Explanation: The decimal is often referred to as the hexadecimal point in hexadecimal representation of numbers.
It is referred to as the octal point in octal numbers.

61. A group of bits used to represent a symbol is called a ____________
a) byte
b) memory
c) nibble
d) code
Answer: a
Explanation: In binary coding, every symbol that appears in data is represented by a group of bits, which are called bytes. Computer codes use binary coding schemes.

62. BCD uses 6 bits to represent a symbol.
a) True
b) False
Answer: a
Explanation: In a Binary Coded Decimal format, 64 characters i.e. 26 different characters can be represented. It is one of the early computer codes.

63. Which of the following is not a type of computer code?
a) EBCDIC
b) BCD
c) ASCII
d) EDIC
Answer: d
Explanation: There is no coding scheme like EDIC. EBCDIC stands for Extended Binary Coded Decimal Interchange Code. BCD stands for Binary Coded Decimal. ASCII stands for American Standard Code for information interchange.

64. The BCD representation of (34)10 is _______________
a) 6
b) 7
c) 8
d) 5
Answer: b
Explanation: BCD numbers are represented as:
34 = (0011 0100)BCD.
Each digit is individually taken and an equivalent standard 4 bit term is written for the respective digit.

65. Perform BCD addition of (23)BCD + (20)BCD .
a) 00110100
b) 01000011
c) 10011
d) 11100
Answer: b
Explanation: To add any two BCD numbers :
Simply perform the addition : 23+20=43.
Then, write the equivalent BCD number = (0100 0011)BCD.

66. The weights used in Binary coded decimal code are:
a) 4,2,1
b) 8,4,2,1
c) 6,4,2,1
d) 2,1
Answer: b
Explanation: BCD is a weighted code and it uses the weights 8,4,2,1 respectively. It is often called the 8421 code. Since, it uses 4 bits for the representation therefore the weights are assigned as : 23 = 8, 22 = 4, 21 = 2, 20 = 1.

67. Write the decimal equivalent for (110001)BCD.
a) 31
b) 13
c) C1
d) 1C
Answer: a
Explanation: To obtain the decimal equivalent :
We start from the rightmost bit and make groups of 4, then write the decimal equivalent accordingly.
0011 0001 = (31)10.

68. The 9’s complement of 45 is _____________
a) 45
b) 54
c) 64
d) 46
Answer: b
Explanation: The 9’s complement of a number is obtained by subtracting each digit from 9. Here, 99-45=54. Therefore, the 9’s complement is 54.

69. The 10’s complement of 455 is _________
a) 543
b) 544
c) 545
d) 546
Answer: c
Explanation: To obtain the 10’s complement, we first obtain the 9’s complement and then add 1 to it.
999-455=544 (9’s)
544+1=545(10’s).

70. The Excess-3 representation of (0100)BCD is __________
a) 0110
b) 1110
c) 0111
d) 1100
Answer: c
Explanation: The excess-3 code is obtained by adding 3 to the BCD code.
Here, 0100+0011=0111.
Also, 4+3=7.

71. What does ASCII stand for?
a) American Standard Code for Information Interchange
b) American Scientific Code for Information Interchange
c) American Scientific Code for Interchanging Information
d) American Standard Code for Interchanging Information
Answer: a
Explanation: The ASCII codes are used to represent the bits into symbols and vice versa. ASCII is the American Standard Code which is used to exchange information.

72. The decimal representation for the character ‘!’ in ASCII is ____________
a) 31
b) 32
c) 33
d) 34
Answer: c
Explanation: The decimal representation of a few basic characters are:
33 : !
34 : ”
35: #
36 :$.

73. The two types of ASCII are _____________ and ____________
a) ASCII-4 and ASCII-8
b) ASCII-8 and ASCII-16
c) ASCII-7 and ASCII-8
d) ASCII-4 and ASCII-16
Answer: c
Explanation: The two types of ASCII are ASCII-7 and ASCII-8. ASCII-7 uses 7 bits for the representation of numbers and ASCII-8 uses 8-bits.

74. Any set of digits or alphabets are generally referred as ______________
a) Characters
b) Symbols
c) Bits
d) Bytes
Answer: a
Explanation: We refer to the digits and alphabets generally as characters. A character is generally a unit of information in computers.

75. The first 128 characters are the same in both the types of ASCII i.e. ASCII-7 and ASCII-8.
a) True
b) False
Answer: a
Explanation: There are two types of ASCII codes: ASCII-7 and ASCII-8. ASCII-7 uses 7 bits to represent a number whereas ASCII-8 uses 8-bits to represent a number.

76. The number of characters that can be represented in ASCII-8 are ______________
a) 128
b) 256
c) 32
d) 64
Answer: b
Explanation: ASCII-8 can represent 256 different characters. ASCII-8 uses 8-bits for the representation of numbers i.e. it can represent 28 = 256 different characters.

77. The zone of alphabetic characters from A to O in ASCII is _____________
a) 1000
b) 0100
c) 0010
d) 0001
Answer: b
Explanation: The zone used by ASCII for alphabets is 0100. For e.g. A is represented as 0100(zone)0001(digit). The hex equivalent is 41 for A. The zone used by numbers is 0011.

78. The representation of the number 8 in binary in ASCII-8 format _________
a) 00111000
b) 01001000
c) 1000
d) 00011000
Answer: a
Explanation: The ASCII-8 format will have 8 bits. The zone for the character 8 is 0011 and the digit is 1000. Therefore, its representation is 00111000.

79. Binary Coding for the letter X is ______________
a) 01011000
b) 00111000
c) 10001000
d) 00010100
Answer: a
Explanation: The binary coding for the letter X is 01011000. Here, 0101 is the zone whereas 1000 is the digit. The alphabets from P to Z have the zone 0101.

80. Express the ASCII equivalent of the signed binary number (00110010)2.
a) 2
b) 1
c) A
d) ,
Answer: a
Explanation: The ASCII characters for the remaining options are:
1 : 00110001
A : 01000001
, : 00101100.

81. The code where all successive numbers differ from their preceding number by single bit is __________
a) Alphanumeric Code
b) BCD
c) Excess 3
d) Gray
Answer: d
Explanation: The code where all successive numbers differ from their preceding number by single bit is gray code. It is an unweighted code. The most important characteristic of this code is that only a single bit change occurs when going from one code number to next. BCD Code is one in which decimal digits are represented by a group of 4-bits each, whereas, in Excess-3 Code, the decimal numbers are incremented by 3 and then written in their BCD format.

82. The following switching functions are to be implemented using a decoder:
f1 = ∑m(1, 2, 4, 8, 10, 14) f2 = ∑m(2, 5, 9, 11) f3 = ∑m(2, 4, 5, 6, 7)
The minimum configuration of decoder will be __________
a) 2 to 4 line
b) 3 to 8 line
c) 4 to 16 line
d) 5 to 32 line
Answer: c
Explanation: 4 to 16 line decoder as the minterms are ranging from 1 to 14.

83. How many AND gates are required to realize Y = CD + EF + G?
a) 4
b) 5
c) 3
d) 2
Answer: d
Explanation: To realize Y = CD + EF + G, two AND gates are required and two OR gates are required.

84. The NOR gate output will be high if the two inputs are __________
a) 00
b) 01
c) 10
d) 11
Answer: a
Explanation: In 01, 10 or 11 output is low if any of the I/P is high. So, the correct option will be 00.

85. How many two-input AND and OR gates are required to realize Y = CD+EF+G?
a) 2, 2
b) 2, 3
c) 3, 3
d) 3, 2
Answer: a
Explanation: Y = CD + EF + G
The number of two input AND gate = 2
The number of two input OR gate = 2.

86. A universal logic gate is one which can be used to generate any logic function. Which of the following is a universal logic gate?
a) OR
b) AND
c) XOR
d) NAND
Answer: d
Explanation: An Universal Logic Gate is one which can generate any logic function and also the three basic gates: AND, OR and NOT. Thus, NOR and NAND can generate any logic function and are thus Universal Logic Gates.

87. A full adder logic circuit will have __________
a) Two inputs and one output
b) Three inputs and three outputs
c) Two inputs and two outputs
d) Three inputs and two outputs
Answer: d
Explanation: A full adder circuit will add two bits and it will also accounts the carry input generated in the previous stage. Thus three inputs and two outputs (Sum and Carry) are there. In case of half adder circuit, there are only two inputs bits and two outputs (SUM and CARRY).

88. How many two input AND gates and two input OR gates are required to realize Y = BD + CE + AB?
a) 3, 2
b) 4, 2
c) 1, 1
d) 2, 3
Answer: a
Explanation: There are three product terms. So, three AND gates of two inputs are required. As only two input OR gates are available, so two OR gates are required to get the logical sum of three product terms.

89. Which of the following are known as universal gates?
a) NAND & NOR
b) AND & OR
c) XOR & OR
d) EX-NOR & XOR
Answer: a
Explanation: The NAND & NOR gates are known as universal gates because any digital circuit can be realized completely by using either of these two gates, and also they can generate the 3 basic gates AND, OR and NOT.

90. The gates required to build a half adder are __________
a) EX-OR gate and NOR gate
b) EX-OR gate and OR gate
c) EX-OR gate and AND gate
d) EX-NOR gate and AND gate
Answer: c
Explanation: The gates required to build a half adder are EX-OR gate and AND gate. EX-OR outputs the SUM of the two input bits whereas AND outputs the CARRY of the two input bits.

91. A single transistor can be used to build which of the following digital logic gates?
a) AND gates
b) OR gates
c) NOT gates
d) NAND gates
Answer: c
Explanation: A transistor can be used as a switch. That is when base is low collector is high (input zero, output one) and base is high collector is low (input 1, output 0).

92. How many truth table entries are necessary for a four-input circuit?
a) 4
b) 8
c) 12
d) 16
Answer: d
Explanation: For 4 inputs: 24 = 16 truth table entries are necessary.

93. Which input values will cause an AND logic gate to produce a HIGH output?
a) At least one input is HIGH
b) At least one input is LOW
c) All inputs are HIGH
d) All inputs are LOW
Answer: c
Explanation: For AND gate, the output is high only when both inputs are high. That’s why the high output in AND will occurs only when all the inputs are high. However, in case of OR gate, if atleast one input is high, the output will be high.

94. Exclusive-OR (XOR) logic gates can be constructed from what other logic gates?
a) OR gates only
b) AND gates and NOT gates
c) AND gates, OR gates, and NOT gates
d) OR gates and NOT gates
Answer: c
Explanation: Expression for XOR is: A.(B’)+(A’).B
So in the above expression, the following logic gates are used: AND, OR, NOT.
Thus, 2 AND gates with two-inputs and 1 OR gate with two-inputs will be required for constructing a XOR gate.

95. The basic logic gate whose output is the complement of the input is the ___________
a) OR gate
b) AND gate
c) INVERTER gate
d) XOR gate
Answer: c
Explanation: It is also called NOT gate and it simply inverts the input, such that 1 becomes 0 and 0 becomes 1.

96. The AND function can be used to ___________ and the OR function can be used to _____________
a) Enable, disable
b) Disable, enable
c) Synchronize, energize
d) Detect, invert
Answer: a
Explanation: The AND gate and OR gate are used for enabling and disabling respectively because of their multiplicity and additivity property. The AND gate outputs 1 when all inputs are at logic 1, whereas the OR gate outputs 0 when all inputs are at logic 0.

97. The dependency notation “>=1” inside a block stands for which operation?
a) OR
b) XOR
c) AND
d) XNOR
Answer: a
Explanation: The dependency notation “>=1” inside a block stands for OR operation.

98. If we use an AND gate to inhibit a signal from passing one of the inputs must be ___________
a) LOW
b) HIGH
c) Inverted
d) Floating
Answer: a
Explanation: AND gate means A*B and OR gate means A+B and to inhibit means to get low signal, one of the input must be low. It means (0*1=0 or 1*0=0) we will get low output signal. Thus, AND gate outputs 1 only when all inputs are at logic level 1 else it outputs 0.

99. Logic gate circuits contain predictable gate functions that open theirs ____________
a) Outputs
b) Inputs
c) Pre-state
d) Impedance state
Answer: b
Explanation: Logic gate circuits contain predictable gate functions that open their inputs because we are free to give any types of inputs.

100. How many NAND circuits are contained in a 7400 NAND IC?
a) 1
b) 2
c) 4
d) 8
Answer: c
Explanation: 7400 IC’s pin has total 14 pin. Pin no 7 use for GND and pin no 14 used for +vcc and remaining pins used for connections. For a NAND gate two inputs are required and one output is obtained means for NAND gate 3 pin connections are required. Thus, a 7400IC contains 4 NAND gates with each having 3 pins. Therefore, total 12 pins dedicated for the NAND operation. Rest 2 pins for power supply.

101. The ______ format is usually used to store data.
a) BCD
b) Decimal
c) Hexadecimal
d) Octal
Answer: a
Explanation: The data usually used by computers have to be stored and represented in a particular format for ease of use.

102. The 8-bit encoding format used to store data in a computer is ______
a) ASCII
b) EBCDIC
c) ANCI
d) USCII
Answer: b
Explanation: The data to be stored in the computers have to be encoded in a particular way so as to provide secure processing of the data.

103. A source program is usually in _______
a) Assembly language
b) Machine level language
c) High-level language
d) Natural language
Answer: c
Explanation: The program written and before being compiled or assembled is called as a source program.

104. Which memory device is generally made of semiconductors?
a) RAM
b) Hard-disk
c) Floppy disk
d) Cd disk
Answer: a
Explanation: Memory devices are usually made of semiconductors for faster manipulation of the contents.

105. The small extremely fast, RAM’s are called as _______
a) Cache
b) Heaps
c) Accumulators
d) Stacks
Answer: a
Explanation: These small and fast memory devices are compared to RAM because they optimize the performance of the system and they only keep files which are required by the current process in them

106. The ALU makes use of _______ to store the intermediate results.
a) Accumulators
b) Registers
c) Heap
d) Stack
Answer: a
Explanation: The ALU is the computational center of the CPU. It performs all mathematical and logical operations. In order to perform better, it uses some internal memory spaces to store immediate results.

107. The control unit controls other units by generating ___________
a) Control signals
b) Timing signals
c) Transfer signals
d) Command Signals
Answer: b
Explanation: This unit is used to control and coordinate between the various parts and components of the CPU.

108. ______ are numbers and encoded characters, generally used as operands.
a) Input
b) Data
c) Information
d) Stored Values
Answer: b
Explanation: None.

109. The Input devices can send information to the processor.
a) When the SIN status flag is set
b) When the data arrives regardless of the SIN flag
c) Neither of the cases
d) Either of the cases
Answer: a
Explanation: The input devices use buffers to store the data received and when the buffer has some data it sends it to the processor.

110. ______ bus structure is usually used to connect I/O devices.
a) Single bus
b) Multiple bus
c) Star bus
d) Rambus
Answer: a
Explanation: BUS is a bunch of wires which carry address, control signals and data. It is used to connect various components of the computer.

111. The I/O interface required to connect the I/O device to the bus consists of ______
a) Address decoder and registers
b) Control circuits
c) Address decoder, registers and Control circuits
d) Only Control circuits
Answer: c
Explanation: The I/O devices are connected to the CPU via BUS and to interact with the BUS they have an interface.

112. To reduce the memory access time we generally make use of ______
a) Heaps
b) Higher capacity RAM’s
c) SDRAM’s
d) Cache’s
Answer: d
Explanation: The time required to access a part of the memory for data retrieval.

113. ______ is generally used to increase the apparent size of physical memory.
a) Secondary memory
b) Virtual memory
c) Hard-disk
d) Disks
Answer: b
Explanation: Virtual memory is like an extension to the existing memory.

114. MFC stands for ___________
a) Memory Format Caches
b) Memory Function Complete
c) Memory Find Command
d) Mass Format Command
Answer: b
Explanation: This is a system command enabled when a memory function is completed by a process.

115. The time delay between two successive initiations of memory operation _______
a) Memory access time
b) Memory search time
c) Memory cycle time
d) Instruction delay
Answer: c
Explanation: The time is taken to finish one task and to start another.

 

1. In parts of the processor, adders are used to calculate ____________
a) Addresses
b) Table indices
c) Increment and decrement operators
d) All of the Mentioned
Answer: d
Explanation: Adders are used to perform the operation of addition. Thus, in parts of the processor, adders are used to calculate addresses, table indices, increment and decrement operators, and similar operations.

2.Total number of inputs in a half adder is __________
a) 2
b) 3
c) 4
d) 1
Answer: a
Explanation: Total number of inputs in a half adder is two. Since, an EXOR gates has 2 inputs and carry is connected with the input of EXOR gates. The output of half-adder is also 2, them being, SUM and CARRY. The output of EXOR gives SUM and that of AND gives carry.

3.In which operation carry is obtained?
a) Subtraction
b) Addition
c) Multiplication
d) Both addition and subtraction
Answer: b
Explanation: In addition, carry is obtained. For example: 1 0 1 + 1 1 1 = 1 0 0; in this example carry is obtained after 1st addition (i.e. 1 + 1 = 1 0). In subtraction, borrow is obtained. Like, 0 – 1 = 1 (borrow 1).

4.If A and B are the inputs of a half adder, the sum is given by __________
a) A AND B
b) A OR B
c) A XOR B
d) A EX-NOR B
Answer: c
Explanation: If A and B are the inputs of a half adder, the sum is given by A XOR B, while the carry is given by A AND B.

5.If A and B are the inputs of a half adder, the carry is given by __________
a) A AND B
b) A OR B
c) A XOR B
d) A EX-NOR B
Answer: a
Explanation: If A and B are the inputs of a half adder, the carry is given by: A(AND)B, while the sum is given by A XOR B.

6.Half-adders have a major limitation in that they cannot __________
a) Accept a carry bit from a present stage
b) Accept a carry bit from a next stage
c) Accept a carry bit from a previous stage
d) Accept a carry bit from the following stages
Answer: c
Explanation: Half-adders have a major limitation in that they cannot accept a carry bit from a previous stage, meaning that they cannot be chained together to add multi-bit numbers. However, the two output bits of a half-adder can also represent the result A+B=3 as sum and carry both being high.

7.The difference between half adder and full adder is __________
a) Half adder has two inputs while full adder has four inputs
b) Half adder has one output while full adder has two outputs
c) Half adder has two inputs while full adder has three inputs
d) All of the Mentioned
Answer: c
Explanation: Half adder has two inputs while full adder has three outputs; this is the difference between them, while both have two outputs SUM and CARRY.

8.If A, B and C are the inputs of a full adder then the sum is given by __________
a) A AND B AND C
b) A OR B AND C
c) A XOR B XOR C
d) A OR B OR C
Answer: c
Explanation: If A, B and C are the inputs of a full adder then the sum is given by A XOR B XOR C.

9.If A, B and C are the inputs of a full adder then the carry is given by __________
a) A AND B OR (A OR B) AND C
b) A OR B OR (A AND B) C
c) (A AND B) OR (A AND B)C
d) A XOR B XOR (A XOR B) AND C
Answer: a
Explanation: If A, B and C are the inputs of a full adder then the carry is given by A AND B OR (A OR B) AND C, which is equivalent to (A AND B) OR (B AND C) OR (C AND A).

10.How many AND, OR and EXOR gates are required for the configuration of full adder?
a) 1, 2, 2
b) 2, 1, 2
c) 3, 1, 2
d) 4, 0, 1
Answer: b
Explanation: There are 2 AND, 1 OR and 2 EXOR gates required for the configuration of full adder, provided using half adder. Otherwise, configuration of full adder would require 3 AND, 2 OR and 2 EXOR.

11.What is a multiplexer?
a) It is a type of decoder which decodes several inputs and gives one output
b) A multiplexer is a device which converts many signals into one
c) It takes one input and results into many output
d) It is a type of encoder which decodes several inputs and gives one output
Answer: b
Explanation: A multiplexer (or MUX) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line, depending on the active select lines.

12.Which combinational circuit is renowned for selecting a single input from multiple inputs & directing the binary information to output line?
a) Data Selector
b) Data distributor
c) Both data selector and data distributor
d) DeMultiplexer
Answer: a
Explanation: Data Selector is another name of Multiplexer. A multiplexer (or MUX) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line, depending on the active select lines.

13.It is possible for an enable or strobe input to undergo an expansion of two or more MUX ICs to the digital multiplexer with the proficiency of large number of ___________
a) Inputs
b) Outputs
c) Selection lines
d) Enable lines
Answer: a
Explanation: It is possible for an enable or strobe input to undergo an expansion of two or more MUX ICs to the digital multiplexer with the proficiency of large number of inputs.

14.Which is the major functioning responsibility of the multiplexing combinational circuit?

a) Decoding the binary information
b) Generation of all minterms in an output function with OR-gate
c) Generation of selected path between multiple sources and a single destination
d) Encoding of binary information
Answer: c
Explanation: The major functioning responsibility of the multiplexing combinational circuit is generation of selected path between multiple sources and a single destination because it makes the circuit too flexible. A multiplexer (or MUX) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line, depending on the active select lines.

15.What is the function of an enable input on a multiplexer chip?
a) To apply Vcc
b) To connect ground
c) To active the entire chip
d) To active one half of the chip
Answer: c
Explanation: Enable input is used to active the chip, when enable is high the chip works (ACTIVE), when enable is low the chip does not work (MEMORY). However, Enable can be Active-High or Active-Low, indicating it is active either when it is connected to VCC or GND respectively.

16.One multiplexer can take the place of ___________
a) Several SSI logic gates
b) Combinational logic circuits
c) Several Ex-NOR gates
d) Several SSI logic gates or combinational logic circuits
Answer: d
Explanation: A multiplexer (or MUX) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line, depending on the active select lines. Since many operational behaviour can be performed by using a multiplexer. Whereas, a combinational circuit is a combination of many logic gates which makes the circuit more complex.

17.A digital multiplexer is a combinational circuit that selects ___________
a) One digital information from several sources and transmits the selected one
b) Many digital information and convert them into one
c) Many decimal inputs and transmits the selected information
d) Many decimal outputs and accepts the selected information
Answer: a
Explanation: A digital multiplexer is a combinational circuit that selects one digital information from several sources and transmits the selected information on a single output line depending on the status of the select lines. That is why it is also known as a data selector.

18.In a multiplexer, the selection of a particular input line is controlled by ___________
a) Data controller
b) Selected lines
c) Logic gates
d) Both data controller and selected lines
Answer: b
Explanation: The selection of a particular input line is controlled by a set of selected lines in a multiplexer, which helps to select a particular input from several sources.

19.If the number of n selected input lines is equal to 2^m then it requires _____ select lines.
a) 2
b) m
c) n
d) 2n
Answer: b
Explanation: If the number of n selected input lines is equal to 2^m then it requires m select lines to select one of m select lines.

20.How many select lines would be required for an 8-line-to-1-line multiplexer?
a) 2
b) 4
c) 8
d) 3
Answer: d
Explanation: 2n input lines, n control lines and 1 output line available for MUX. Here, 8 input lines mean 23 inputs. So, 3 control lines are possible. Depending on the status of the select lines, the input is selected and fed to the output.

21.Why is a demultiplexer called a data distributor?
a) The input will be distributed to one of the outputs
b) One of the inputs will be selected for the output
c) The output will be distributed to one of the inputs
d) Single input to Single Output
Answer: a
Explanation: A demultiplexer sends a single input to multiple outputs, depending on the select lines. For one input, the demultiplexer gives several outputs. That is why, it is called a data distributor.

22.Most demultiplexers facilitate which type of conversion?
a) Decimal-to-hexadecimal
b) Single input, multiple outputs
c) AC to DC
d) Odd parity to even parity
Answer: b
Explanation: A demultiplexer sends a single input to multiple outputs, depending on the select lines. Demultiplexer converts single input into multiple outputs.

23.In 1-to-4 demultiplexer, how many select lines are required?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: The formula for total no. of outputs is given by 2n, where n is the no. of select lines. Therefore, for 1:4 demultiplexer, 2 select lines are required.

24.In a multiplexer the output depends on its ___________
a) Data inputs
b) Select inputs
c) Select outputs
d) Enable pin
Answer: b
Explanation: A demultiplexer sends a single input to multiple outputs, depending on the select lines. As the select input changes, the output of the multiplexer varies according to that input.

25. How many select lines are required for a 1-to-8 demultiplexer?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: The formula for total no. of outputs is given by 2n, where n is the no. of select lines. In this case n = 3 since 23 = 8.

26.How many AND gates are required for a 1-to-8 multiplexer?
a) 2
b) 6
c) 8
d) 5
Answer: c
Explanation: The number of AND gates required will be equal to the number of outputs in a demultiplexer, which are 8.

27.Which IC is used for the implementation of 1-to-16 DEMUX?
a) IC 74154
b) IC 74155
c) IC 74139
d) IC 74138
Answer: a
Explanation: IC 74154 is used for the implementation of 1-to-16 DEMUX, whose output is inverted input

28.Latches constructed with NOR and NAND gates tend to remain in the latched condition due to which configuration feature?
a) Low input voltages
b) Synchronous operation
c) Gate impedance
d) Cross coupling
Answer: d
Explanation: Latch is a type of bistable multivibrator having two stable states. Both inputs of a latch are directly connected to the other’s output. Such types of structure is called cross coupling and due to which latches remain in the latched condition.

29.One example of the use of an S-R flip-flop is as ___________
a) Transition pulse generator
b) Racer
c) Switch debouncer
d) Astable oscillator
Answer: c
Explanation: The SR flip-flop is very effective in removing the effects of switch bounce, which is the unwanted noise caused during the switching of electronic devices.

30.The truth table for an S-R flip-flop has how many VALID entries?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: The SR flip-flop actually has three inputs, Set, Reset and its current state. The Invalid or Undefined State occurs at both S and R being at 1.

31.When both inputs of a J-K flip-flop cycle, the output will ___________
a) Be invalid
b) Change
c) Not change
d) Toggle
Answer: c
Explanation: After one cycle the value of each input comes to the same value. Eg: Assume J=0 and K=1. After 1 cycle, it becomes as J=0->1->0(1 cycle complete) and K=1->0->1(1 cycle complete). The J & K flip-flop has 4 stable states: Latch, Reset, Set and Toggle.

32.Which of the following is correct for a gated D-type flip-flop?
a) The Q output is either SET or RESET as soon as the D input goes HIGH or LOW
b) The output complement follows the input when enabled
c) Only one of the inputs can be HIGH at a time
d) The output toggles if one of the inputs is held HIGH
Answer: a
Explanation: In D flip flop, when the clock is high then the output depends on the input otherwise reminds previous output. In a state of clock high, when D is high the output Q also high, if D is ‘0’ then output is also zero. Like SR flip-flop, the D-flip-flop also have an invalid state at both inputs being 1.

33.A basic S-R flip-flop can be constructed by cross-coupling of which basic logic gates?
a) AND or OR gates
b) XOR or XNOR gates
c) NOR or NAND gates
d) AND or NOR gates
Answer: c
Explanation: The basic S-R flip-flop can be constructed by cross coupling of NOR or NAND gates. Cross coupling means the output of second gate is fed to the input of first gate and vice-versa.

34.The logic circuits whose outputs at any instant of time depends only on the present input but also on the past outputs are called
a) Combinational circuits
b) Sequential circuits
c) Latches
d) Flip-flops
Answer: b
Explanation: In sequential circuits, the output signals are fed back to the input side. So, The circuits whose outputs at any instant of time depends only on the present input but also on the past outputs are called sequential circuits. Unlike sequential circuits, if output depends only on the present state, then it’s known as combinational circuits.

35.Whose operations are more faster among the following?
a) Combinational circuits
b) Sequential circuits
c) Latches
d) Flip-flops
Answer: a
Explanation: Combinational circuits are often faster than sequential circuits. Since, the combinational circuits do not require memory elements whereas the sequential circuits need memory devices to perform their operations in sequence. Latches and Flip-flops come under sequential circuits.

36.How many types of sequential circuits are?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two type of sequential circuits viz., (i) synchronous or clocked and (ii) asynchronous or unclocked. Synchronous Sequential Circuits are triggered in the presence of a clock signal, whereas, Asynchronous Sequential Circuits function in the absence of a clock signal.

37.The sequential circuit is also called ___________
a) Flip-flop
b) Latch
c) Strobe
d) Adder
Answer: b
Explanation: The sequential circuit is also called a latch because both are a memory cell, which are capable of storing one bit of information.

38.The basic latch consists of ___________
a) Two inverters
b) Two comparators
c) Two amplifiers
d) Two adders
Answer: a
Explanation: The basic latch consists of two inverters. It is in the sense that if the output Q = 0 then the second output Q’ = 1 and vice versa.

39.In S-R flip-flop, if Q = 0 the output is said to be ___________
a) Set
b) Reset
c) Previous state
d) Current state
Answer: b
Explanation: In S-R flip-flop, if Q = 0 the output is said to be reset and set for Q = 1.

40.The output of latches will remain in set/reset untill ___________
a) The trigger pulse is given to change the state
b) Any pulse given to go into previous state
c) They don’t get any pulse more
d) The pulse is edge-triggered
Answer: a
Explanation: The output of latches will remain in set/reset untill the trigger pulse is given to change the state.

41.A register is defined as ___________
a) The group of latches for storing one bit of information
b) The group of latches for storing n-bit of information
c) The group of flip-flops suitable for storing one bit of information
d) The group of flip-flops suitable for storing binary information
Answer: d
Explanation: A register is defined as the group of flip-flops suitable for storing binary information. Each flip-flop is a binary cell capable of storing one bit of information. The data in a register can be transferred from one flip-flop to another.

42.The register is a type of ___________
a) Sequential circuit
b) Combinational circuit
c) CPU
d) Latches
Answer: a
Explanation: Register’s output depends on the past and present states of the inputs. The device which follows these properties is termed as a sequential circuit. Whereas, combinational circuits only depend on the present values of inputs.

43.How many types of registers are?
a) 2
b) 3
c) 4
d) 5
Answer: c
Explanation: There are 4 types of shift registers, viz., Serial-In/Serial-Out, Serial-In/Parallel-Out, Parallel-In/Serial-Out and Parallel-In/Parallel-Out.

44.The main difference between a register and a counter is ___________
a) A register has no specific sequence of states
b) A counter has no specific sequence of states
c) A register has capability to store one bit of information but counter has n-bit
d) A register counts data
Answer: a
Explanation: The main difference between a register and a counter is that a register has no specific sequence of states except in certain specialised applications.

45.In D register, ‘D’ stands for ___________
a) Delay
b) Decrement
c) Data
d) Decay
Answer: c
Explanation: D stands for “data” in case of flip-flops and not delay. Registers are made of a group of flip-flops.

50.Registers capable of shifting in one direction is ___________
a) Universal shift register
b) Unidirectional shift register
c) Unipolar shift register
d) Unique shift register
Answer: b
Explanation: The register capable of shifting in one direction is unidirectional shift register. The register capable of shifting in both directions is known as a bidirectional shift register.

51.A register that is used to store binary information is called ___________
a) Data register
b) Binary register
c) Shift register
d) D – Register
Answer: b
Explanation: A register that is used to store binary information is called a binary register. A register in which data can be shifted is called shift register.

52.A shift register is defined as ___________
a) The register capable of shifting information to another register
b) The register capable of shifting information either to the right or to the left
c) The register capable of shifting information to the right only
d) The register capable of shifting information to the left only
Answer: b
Explanation: The register capable of shifting information either to the right or to the left is termed as shift register. A register in which data can be shifted only in one direction is called unidirectional shift register, while if data can shifted in both directions, it is known as a bidirectional shift register.

53.How many methods of shifting of data are available?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two types of shifting of data are available and these are serial shifting & parallel shifting.

54.In serial shifting method, data shifting occurs ____________
a) One bit at a time
b) simultaneously
c) Two bit at a time
d) Four bit at a time
Answer: a
Explanation: As the name suggests serial shifting, it means that data shifting will take place one bit at a time for each clock pulse in a serial fashion. While in parallel shifting, shifting will take place with all bits simultaneously for each clock pulse in a parallel fashion.

module 1

Module 2

1. The ______ format is usually used to store data.
a) BCD
b) Decimal
c) Hexadecimal
d) Octal
Answer: a
Explanation: The data usually used by computers have to be stored and represented in a particular format for ease of use.

2. The 8-bit encoding format used to store data in a computer is ______
a) ASCII
b) EBCDIC
c) ANCI
d) USCII
Answer: b
Explanation: The data to be stored in the computers have to be encoded in a particular way so as to provide secure processing of the data.

3. A source program is usually in _______
a) Assembly language
b) Machine level language
c) High-level language
d) Natural language
Answer: c
Explanation: The program written and before being compiled or assembled is called as a source program.

4. Which memory device is generally made of semiconductors?
a) RAM
b) Hard-disk
c) Floppy disk
d) Cd disk
Answer: a
Explanation: Memory devices are usually made of semiconductors for faster manipulation of the contents.

5. The small extremely fast, RAM’s are called as _______
a) Cache
b) Heaps
c) Accumulators
d) Stacks
Answer: a
Explanation: These small and fast memory devices are compared to RAM because they optimize the performance of the system and they only keep files which are required by the current process in them

6. The ALU makes use of _______ to store the intermediate results.
a) Accumulators
b) Registers
c) Heap
d) Stack
Answer: a
Explanation: The ALU is the computational center of the CPU. It performs all mathematical and logical operations. In order to perform better, it uses some internal memory spaces to store immediate results.

7. The control unit controls other units by generating ___________
a) Control signals
b) Timing signals
c) Transfer signals
d) Command Signals
Answer: b
Explanation: This unit is used to control and coordinate between the various parts and components of the CPU.

8. ______ are numbers and encoded characters, generally used as operands.
a) Input
b) Data
c) Information
d) Stored Values
Answer: b
Explanation: None.

9. The Input devices can send information to the processor.
a) When the SIN status flag is set
b) When the data arrives regardless of the SIN flag
c) Neither of the cases
d) Either of the cases
Answer: a
Explanation: The input devices use buffers to store the data received and when the buffer has some data it sends it to the processor.

10. ______ bus structure is usually used to connect I/O devices.
a) Single bus
b) Multiple bus
c) Star bus
d) Rambus
Answer: a
Explanation: BUS is a bunch of wires which carry address, control signals and data. It is used to connect various components of the computer.

11. The I/O interface required to connect the I/O device to the bus consists of ______
a) Address decoder and registers
b) Control circuits
c) Address decoder, registers and Control circuits
d) Only Control circuits
Answer: c
Explanation: The I/O devices are connected to the CPU via BUS and to interact with the BUS they have an interface.

12. To reduce the memory access time we generally make use of ______
a) Heaps
b) Higher capacity RAM’s
c) SDRAM’s
d) Cache’s
Answer: d
Explanation: The time required to access a part of the memory for data retrieval.

13. ______ is generally used to increase the apparent size of physical memory.
a) Secondary memory
b) Virtual memory
c) Hard-disk
d) Disks
Answer: b
Explanation: Virtual memory is like an extension to the existing memory.

14. MFC stands for ___________
a) Memory Format Caches
b) Memory Function Complete
c) Memory Find Command
d) Mass Format Command
Answer: b
Explanation: This is a system command enabled when a memory function is completed by a process.

15. The time delay between two successive initiations of memory operation _______
a) Memory access time
b) Memory search time
c) Memory cycle time
d) Instruction delay
Answer: c
Explanation: The time is taken to finish one task and to start another.
16. The decoded instruction is stored in ______
a) IR
b) PC
c) Registers
d) MDR
Answer: a
Explanation: The instruction after obtained from the PC, is decoded and operands are fetched and stored in the IR.

17. The instruction -> Add LOCA, R0 does _______
a) Adds the value of LOCA to R0 and stores in the temp register
b) Adds the value of R0 to the address of LOCA
c) Adds the values of both LOCA and R0 and stores it in R0
d) Adds the value of LOCA with a value in accumulator and stores it in R0
Answer: c
Explanation: None.

18. Which registers can interact with the secondary storage?
a) MAR
b) PC
c) IR
d) R0
Answer: a
Explanation: MAR can interact with secondary storage in order to fetch data from it.

19. During the execution of a program which gets initialized first?
a) MDR
b) IR
c) PC
d) MAR
Answer: c
Explanation: For the execution of a process first the instruction is placed in the PC.

20. Which of the register/s of the processor is/are connected to Memory Bus?
a) PC
b) MAR
c) IR
d) Both PC and MAR
Answer: b
Explanation: MAR is connected to the memory BUS in order to access the memory.

21. ISP stands for _________
a) Instruction Set Processor
b) Information Standard Processing
c) Interchange Standard Protocol
d) Interrupt Service Procedure
Answer: a
Explanation: None.

22. The internal components of the processor are connected by _______
a) Processor intra-connectivity circuitry
b) Processor bus
c) Memory bus
d) Rambus
Answer: b
Explanation: The processor BUS is used to connect the various parts in order to provide a direct connection to the CPU.

23. ______ is used to choose between incrementing the PC or performing ALU operations.
a) Conditional codes
b) Multiplexer
c) Control unit
d) None of the mentioned
Answer: b
Explanation: The multiplexer circuit is used to choose between the two as it can give different results based on the input.

24. The registers, ALU and the interconnection between them are collectively called as _____
a) process route
b) information trail
c) information path
d) data path
Answer: d
Explanation: The Operational and processing part of the CPU are collectively called as a data path.

25. _______ is used to store data in registers.
a) D flip flop
b) JK flip flop
c) RS flip flop
d) None of the mentioned
Answer: a
Explanation: None.

26. During the execution of the instructions, a copy of the instructions is placed in the ______
a) Register
b) RAM
c) System heap
d) Cache
Answer: d
Explanation: None.

27. Two processors A and B have clock frequencies of 700 Mhz and 900 Mhz respectively. Suppose A can execute an instruction with an average of 3 steps and B can execute with an average of 5 steps. For the execution of the same instruction which processor is faster?
a) A
b) B
c) Both take the same time
d) Insufficient information
Answer: a
Explanation: The performance of a system can be found out using the Basic performance formula.

28. A processor performing fetch or decoding of different instruction during the execution of another instruction is called ______
a) Super-scaling
b) Pipe-lining
c) Parallel Computation
d) None of the mentioned
Answer: b
Explanation: Pipe-lining is the process of improving the performance of the system by processing different instructions at the same time, with only one instruction performing one specific operation.

29. For a given FINITE number of instructions to be executed, which architecture of the processor provides for a faster execution?
a) ISA
b) ANSA
c) Super-scalar
d) All of the mentioned
Answer: c
Explanation: In super-scalar architecture, the instructions are set in groups and they’re decoded and executed together reducing the amount of time required to process them.

30. The clock rate of the processor can be improved by _________
a) Improving the IC technology of the logic circuits
b) Reducing the amount of processing done in one step
c) By using the overclocking method
d) All of the mentioned
Answer: d
Explanation: The clock rate(frequency of the processor) is the hardware dependent quantity it is fixed for a given processor.

31. An optimizing Compiler does _________
a) Better compilation of the given piece of code
b) Takes advantage of the type of processor and reduces its process time
c) Does better memory management
d) None of the mentioned
Answer: b
Explanation: An optimizing compiler is a compiler designed for the specific purpose of increasing the operation speed of the processor by reducing the time taken to compile the program instructions.

32.. The ultimate goal of a compiler is to ________
a) Reduce the clock cycles for a programming task
b) Reduce the size of the object code
c) Be versatile
d) Be able to detect even the smallest of errors
Answer: a
Explanation: None.

33. SPEC stands for _______
a) Standard Performance Evaluation Code
b) System Processing Enhancing Code
c) System Performance Evaluation Corporation
d) Standard Processing Enhancement Corporation
Answer: c
Explanation: SPEC is a corporation that started to standardize the evaluation method of a system’s performance.

34. As of 2000, the reference system to find the performance of a system is _____
a) Ultra SPARC 10
b) SUN SPARC
c) SUN II
d) None of the mentioned
Answer: a
Explanation: In SPEC system of measuring a system’s performance, a system is used as a reference against which other systems are compared and performance is determined.

35.When Performing a looping operation, the instruction gets stored in the ______
a) Registers
b) Cache
c) System Heap
d) System stack
Answer: b
Explanation: When a looping or branching operation is carried out the offset value is stored in the cache along with the data.

36. The average number of steps taken to execute the set of instructions can be made to be less than one by following _______
a) ISA
b) Pipe-lining
c) Super-scaling
d) Sequential
Answer: c
Explanation: The number of steps required to execute a given set of instructions is sufficiently reduced by using super-scaling. In this method, a set of instructions are grouped together and are processed.

37. If a processor clock is rated as 1250 million cycles per second, then its clock period is ________
a) 1.9 * 10-10 sec
b) 1.6 * 10-9 sec
c) 1.25 * 10-10 sec
d) 8 * 10-10 sec
Answer: d
Explanation: None.

38. If the instruction, Add R1, R2, R3 is executed in a system that is pipe-lined, then the value of S is (Where S is a term of the Basic performance equation)?
a) 3
b) ~2
c) ~1
d) 6
Answer: c
Explanation: S is the number of steps required to execute the instructions.

39. CISC stands for _______
a) Complete Instruction Sequential Compilation
b) Computer Integrated Sequential Compiler
c) Complex Instruction Set Computer
d) Complex Instruction Sequential Compilation
Answer: c
Explanation: CISC is a type of system architecture where complex instructions are grouped together and executed to improve system performance.

40. As of 2000, the reference system to find the SPEC rating are built with _____ Processor.
a) Intel Atom SParc 300Mhz
b) Ultra SPARC -IIi 300MHZ
c) Amd Neutrino series
d) ASUS A series 450 Mhz
Answer: b
Explanation: None.

41.How many types of architectures are available, for designing a device that is able to work on its own?
a) 3
b) 2
c) 1
d) 4
Answer: b
Explanation: There are basically two main types of architectures present, they are Von Neumann and Harvard architectures.

42. Which architecture is followed by general purpose microprocessors?
a) Harvard architecture
b) Von Neumann architecture
c) None of the mentioned
d) All of the mentioned
Answer: b
Explanation: General purpose microprocessors make use of Von Neumann architecture as here a simpler design is offered.

43.Which architecture involves both the volatile and the non volatile memory?
a) Harvard architecture
b) Von Neumann architecture
c) None of the mentioned
d) All of the mentioned
Answer: a
Explanation: In Harvard architecture, both the volatile and the non volatile memories are involved. This is done to increase its efficiency as both the memories are being used over here.

44.Which architecture provides separate buses for program and data memory?
a) Harvard architecture
b) Von Neumann architecture
c) None of the mentioned
d) All of the mentioned
Answer: a
Explanation: Harvard Architecture provides separated buses for data and program memory to fetch program and data simultaneously. By doing this access time is reduced and hence performance is increased.

45.Which microcontroller doesn’t match with its architecture below?
a) Microchip PIC- Harvard
b) MSP430- Harvard
c) ARM7- Von Neumann
d) ARM9- Harvard
Answer: b
Explanation: MSP430 supports Von Neumann architecture.

46. Harvard architecture has _____________
a) dedicated buses for data and program memory
b) pipeline technique
c) complex architecture
d) all of the mentioned
Answer: d
Explanation: Harvard Architecture has dedicated buses for data and program memory and pipeline technique because of this architecture is complex.

47. Which out of the following supports Harvard architecture?
a) ARM7
b) Pentium
c) SHARC
d) All of the mentioned
Answer: c
Explanation: SHARC supports harvard architecture for signal processing in DSP.

48. Why most of the DSPs use Harvard architecture?
a) they provide greater bandwidth
b) they provide more predictable bandwidth
c) they provide greater bandwidth & also more predictable bandwidth
d) none of the mentioned
Answer: c
Explanation: Most of the DSPs use harvard architecture because they provide a wider predictable bandwidth.

49. Which of the following supports CISC as well as Harvard architecture?
a) ARM7
b) ARM9
c) SHARC
d) None of the mentioned
Answer: c
Explanation: SHARC supports both the CISC and the Harvard architecture.

50. Which of the two architecture saves memory?
a) Harvard
b) Von Neumann
c) Harvard & Von Neumann
d) None of the mentioned
Answer: b
Explanation: As only one memory is present in the Von Neumann architecture so it saves a lot of memory.

51. The instruction, MOV AX, 0005H belongs to the address mode
a) register
b) direct
c) immediate
d) register relative
Answer: c
Explanation: In Immediate addressing mode, immediate data is a part of instruction and appears in the form of successive byte or bytes.

52. The instruction, MOV AX, 1234H is an example of
a) register addressing mode
b) direct addressing mode
c) immediate addressing mode
d) based indexed addressing mode
Answer: c
Explanation: Since immediate data is present in the instruction.

53. The instruction, MOV AX, [2500H] is an example of
a) immediate addressing mode
b) direct addressing mode
c) indirect addressing mode
d) register addressing mode
Answer: b
Explanation: Since the address is directly specified in the instruction as a part of it.

54. If the data is present in a register and it is referred using the particular register, then it is
a) direct addressing mode
b) register addressing mode
c) indexed addressing mode
d) immediate addressing mode
Answer: b
Explanation: Since register is used to refer the address.

55. The instruction, MOV AX,[BX] is an example of
a) direct addressing mode
b) register addressing mode
c) register relative addressing mode
d) register indirect addressing mode
Answer: d
Explanation: Since the register used to refer to the address is accessed indirectly.

56. If the offset of the operand is stored in one of the index registers, then it is
a) based indexed addressing mode
b) relative based indexed addressing mode
c) indexed addressing mode
d) none of the mentioned
Answer: c
Explanation: In the indexed addressing mode, the offset of an operand is stored and in the rest of them, address is stored.

57. The addressing mode that is used in unconditional branch instructions is
a) intrasegment direct addressing mode
b) intrasegment indirect addressing mode
c) intrasegment direct and indirect addressing mode
d) intersegment direct addressing mode
Answer: b
Explanation: In intrasegment indirect mode, the branch address is found as the content of a register or a memory location.

58. If the location to which the control is to be transferred lies in a different segment other than the current one, then the mode is called
a) intrasegment mode
b) intersegment direct mode
c) intersegment indirect mode
d) intersegment direct and indirect mode
Answer: d
Explanation: In intersegment mode, the control to be transferred lies in a different segment.

59. The instruction, JMP 5000H:2000H;
is an example of
a) intrasegment direct mode
b) intrasegment indirect mode
c) intersegment direct mode
d) intersegment indirect mode
Answer: c
Explanation: Since in intersegment direct mode, the address to which the control is to be transferred is in a different segment.

60. The contents of a base register are added to the contents of index register in
a) indexed addressing mode
b) based indexed addressing mode
c) relative based indexed addressing mode
d) based indexed and relative based indexed addressing mode
Answer: d
Explanation: The effective address is formed by adding the contents of both base and index registers to a default segment.

61. If a number of instructions are repeating through the main program, then to reduce the length of the program, __________ is used.
a) procedure
b) subroutine
c) macro
d) none of the mentioned
Answer: c
Explanation: For a certain number of instructions that are repeated in the main program, when macro is defined then the code of a program is reduced by placing the name of the macro at which the set of instructions are needed to be repeated.

62. The process of assigning a label or macroname to the string is called
a) initialising macro
b) initialising string macro
c) defining a string macro
d) defining a macro
Answer: d
Explanation: The process of assigning a label to the string is called defining a macro.

63. A macro within a macro is called
a) macro-within-macro
b) nested macro
c) macro-in-macro
d) none of the mentioned
Answer: b
Explanation: A macro may be called from inside a macro. This type of macro is called nested macro.

64. A macro can be defined as
a) beginning of a program
b) end of a program
c) after initialisation of program
d) anywhere in a program
Answer: d
Explanation: A macro can be defined anywhere in a program.

65. A macro can be used as ________
a) in data segment
b) to represent directives
c) to represent statements
d) all of the mentioned
Answer: d
Explanation: A macro may be used in data segment and can also be used to represent statements and directives.

66. The end of a macro can be represented by the directive.
a) END
b) ENDS
c) ENDM
d) ENDD
Answer: c
Explanation: The ENDM directive marks the end of the instructions or statements sequence assigned with the macro name.

67. Inserting the statements and instructions represented by macro, directly at the place of the macroname, in the program, is known as
a) calling a macro
b) inserting a macro
c) initializing a macro
d) none of the mentioned
Answer: a
Explanation: Inserting the statements and instructions at the place of macroname, in the program, is known as calling a macro.

68. The time required for execution of a macro is ________ that of the procedure.
a) greater than
b) less than
c) equal to
d) none of the mentioned
Answer: b
Explanation: The time required for execution of a macro is less than that of procedure as it does not contain CALL and RET instructions as the procedures do.

69. Which of the following statements is incorrect?
a) complete code of instruction string is inserted at each place, wherever the macroname appears
b) macro requires less time of execution than that of procedure
c) macro uses stack memory
d) macroname can be anything except registers and mnemonics
Answer: c
Explanation: Macro does not require stack memory and hence has less time for execution.

70. The beginning of the macro can be represented as
a) START
b) BEGIN
c) MACRO
d) None of the mentioned
Answer: c
Explanation: The beginning of the macro is represented as macroname followed by the directive MACRO.
SYNTAX: macroname MACRO
EXAMPLE: STRINGS MACRO.

71. The Stack follows the sequence
a) first-in-first-out
b) first-in-last-out
c) last-in-first-out
d) last-in-last-out
Answer: c
Explanation: The stack follows last-in-first-out sequence.

72. If the processor is executing the main program that calls a subroutine, then after executing the main program up to the CALL instruction, the control will be transferred to
a) address of main program
b) subroutine address
c) address of CALL instruction
d) none of the mentioned
Answer: b
Explanation: Since subroutine is called, to start the execution of the subroutine, the control is transferred to the subroutine address.

73. The stack is useful for
a) storing the register status of the processor
b) temporary storage of data
c) storing contents of registers temporarily inside the CPU
d) all of the mentioned
Answer: d
Explanation: Stack is used for temporary storage of contents of registers and memory locations, status of registers.

74. The Stack is accessed using
a) SP register
b) SS register
c) SP and SS register
d) None of the mentioned
Answer: c
Explanation: The stack is accessed using a pointer that is implemented using SP and SS registers.

75. As the storing of data words onto the stack is increased, the stack pointer is
a) incremented by 1
b) decremented by 1
c) incremented by 2
d) decremented by 2
Answer: d
Explanation: The data is stored from top address of the stack and is decremented by 2.

76. While retrieving data from the stack, the stack pointer is
a) incremented by 1
b) incremented by 2
c) decremented by 1
d) decremented by 2
Answer: b
Explanation: The data in the stack, may again be transferred back from a stack to register. At that time, the stack pointer is incremented by 2.

77. The process of storing the data in the stack is called ……… the stack.
a) pulling into
b) pulling out
c) pushing into
d) popping into
Answer: c
Explanation: The data is pushed into the stack while loading the stack.

78. The reverse process of transferring the data back from the stack to the CPU register is known as
a) pulling out the stack
b) pushing out the stack
c) popping out the stack
d) popping off the stack
Answer: d
Explanation: The data retrieved from stack is called popping off.

79. The books arranged one on the other on a table is an example of
a) queue
b) queue and first-in-first out
c) stack
d) stack and last-in-first-out
Answer: d
Explanation: If the books are arranged one on the other, then the book that is placed last will be the first out.

80. The PID temperature controller using 8086 has
a) data flow
b) data flow and uses queue
c) sequential flow
d) sequential flow and uses stack
Answer: d
Explanation: Since PID temperature controller has steps that need to be sequentially executed such as sampling the output, conversion of a signal with ADC, finding errors, deriving control signals and applying the control signal to control flow of energy.

81.Which of the following assembler directives are used to define a Procedure in the 8086 microprocessor?
a) PROCEDURE and ENDP
b) STARTP and ENDP
c) PROC and ENDPROC
d) None of the above
Answer: d. None of the above

82.Which of the following features is not offered by Macros?
a).Code reusability
b).Less memory space
c).Fast execution
d).None of the above
Answer: b. Less Memory Space

83.Which of the following is the correct syntax for calling a Macro?
a).MACRO macro_name
b).MACRO macro_name [ parameter’s list]
c).macro_name [parameter’s list ]
d).None of the above
Answer: c. macro_name [parameter’s list ]

84.Which of the following characteristics of Procedures makes it unfit for being used for short instruction sets with less number of instructions?
a).Extra code requirement for integrating procedures
b).Linking of procedures with the mainline program takes too much time
c).Extra work load on processor for shifting controls
d).All of the Above
Answer: d. All of the above

85.In a program, a Macro is being called ‘n’ times. Then how many times is the machine code generated for the same?
a).1 time
b).’n’ times
c).’n-1′ times
d).None of the above
Answer: b. ‘n’ times

Module 3

1. Which of the following is true about Computer Architecture?
A. It acts as the interface between hardware and software.
B. Computer Architecture tells us how exactly all the units in the system are arranged and interconnected.
C. Computer Architecture is concerned with the structure and behaviour of a computer system as seen by the user.
D. It involves Physical Components
Ans : A
Explanation: It acts as the interface between hardware and software is true statement and all other statement are related to Computer Organization.

2. Which of the following is true about Computer Organization?
A. It deals with high-level design issues.
B. It involves Logic (Instruction sets, Addressing modes, Data types, Cache optimization).
C. Computer Organization tells us how exactly all the units in the system are arranged and interconnected.
D. None of the Above
Ans : C
Explanation: Computer Organization tells us how exactly all the units in the system are arranged and interconnected is true about Computer Organization and all other statement are related to Computer Architecture.

3. Which format is used to store data?
A. BCH
B. BCD
C. Binary
D. Decimal
Ans : B
Explanation: BCD format is used to store data.

4. The program written and before being compiled or assembled is called ____________.
A. Start Program
B. Intermediate program
C. Source Program
D. Natural Program
Ans : C
Explanation: The program written and before being compiled or assembled is called Source Program.

5. The ________ is the computational center of the CPU.
A. Registers
B. ALU
C. Flip-Flop
D. Multiplexer
Ans : B
Explanation: The ALU is the computational center of the CPU.

6. The input devices use _______ to store the data received
A. Primary Memory
B. Secondary Memory
C. Buffer
D. External Memory
Ans : C
Explanation: The input devices use buffers to store the data received and when the buffer has some data it sends it to the processor.

7. The I/O devices are connected to the CPU via __________.
A. SDRAM’s
B. Control circuits
C. Signals
D. BUS
Ans : D
Explanation: The I/O devices are connected to the CPU via BUS.

8. An optimizing Compiler does _________
A. Better compilation of the given piece of code
B. Takes advantage of the type of processor and reduces its process time
C. Does better memory management
D. All of the above
Ans : B
Explanation: An optimizing compiler is a compiler designed for the specific purpose of increasing the operation speed of the processor by reducing the time taken to compile the program instructions.

9. Which bus is used to connect the monitor to the CPU?
A. Single Bus
B. SCSI Bus
C. Multiple Bus
D. Rambus
Ans : B
Explanation: SCSI BUS is usually used to connect video devices to the processor.

10. Which of the following is used to choose between incrementing the PC or performing ALU operations?
A. Conditional Units
B. Multiplexer
C. Control Codes
D. Memory bus
Ans : B
Explanation: The multiplexer circuit is used to choose between the two as it can give different results based on the input.

11. RTN stands for ___________
a) Register Transfer Notation
b) Register Transmission Notation
c) Regular Transmission Notation
d) Regular Transfer Notation
Answer: a
Explanation: This is the way of writing the assembly language code with the help of register notations.

12. The instruction, Add Loc,R1 in RTN is _______
a) AddSetCC Loc+R1
b) R1=Loc+R1
c) Not possible to write in RTN
d) R1<-[Loc]+[R1]
Answer: d
Explanation: None.

13. Can you perform an addition on three operands simultaneously in ALN using Add instruction?
a) Yes
b) Not possible using Add, we’ve to use AddSetCC
c) Not permitted
d) None of the mentioned
Answer: c
Explanation: You cannot perform an addition on three operands simultaneously because the third operand is where the result is stored.

14. The instruction, Add R1,R2,R3 in RTN is _______
a) R3=R1+R2+R3
b) R3<-[R1]+[R2]+[R3]
c) R3=[R1]+[R2]
d) R3<-[R1]+[R2]
Answer: d
Explanation: In RTN the first operand is the destination and the second operand is the source.

15. In a system, which has 32 registers the register id is __________ long.
a) 16 bit
b) 8 bits
c) 5 bits
d) 6 bits
Answer: c
Explanation: The ID is the name tag given to each of the registers and used to identify them.

16. The two phases of executing an instruction are __________
a) Instruction decoding and storage
b) Instruction fetch and instruction execution
c) Instruction execution and storage
d) Instruction fetch and Instruction processing
Answer: b
Explanation: First, the instructions are fetched and decoded and then they’re executed and stored.

17. The Instruction fetch phase ends with _________
a) Placing the data from the address in MAR into MDR
b) Placing the address of the data into MAR
c) Completing the execution of the data and placing its storage address into MAR
d) Decoding the data in MDR and placing it in IR
Answer: d
Explanation: The fetch ends with the instruction getting decoded and being placed in the IR and the PC getting incremented.

18. While using the iterative construct (Branching) in execution _____________ instruction is used to check the condition.
a) TestAndSet
b) Branch
c) TestCondn
d) None of the mentioned
Answer: b
Explanation: Branch instruction is used to check the test condition and to perform the memory jump with the help of offset.

19. When using Branching, the usual sequencing of the PC is altered. A new instruction is loaded which is called as ______
a) Branch target
b) Loop target
c) Forward target
d) Jump instruction
Answer: a
Explanation: None.

20. The condition flag Z is set to 1 to indicate _______
a) The operation has resulted in an error
b) The operation requires an interrupt call
c) The result is zero
d) There is no empty register available
Answer: c
Explanation: This condition flag is used to check if the arithmetic operation yields a zero output.

21. ____________ is the raw material used as input and __________ is the processed data obtained as output of data processing.
a) Data, Instructions
b) Instructions, Program
c) Data, Program
d) Program, Code
Answer: a
Explanation: Data can be assumed as a raw material which, in turns after processing gives the desired output in the form of instructions. Further, a set of ordered and meaningful instructions is known as a program.

22. Which of the following is not a characteristic of a computer?
a) Diligence
b) I.Q.
c) Accuracy
d) Versatility
Answer: b
Explanation: The Computer system has no I.Q. of its own. It does only what it is programmed to do. It cannot take decisions of its own.
A computer is diligent because it can work continuously for hours without getting any errors or without getting grumbled.
The accuracy of a computer is consistently high and its level of accuracy depends on its design. A computer can perform any task if, it can be broken down into a series of logical steps. Therefore, a computer is versatile.

23. Fill in the blank in the diagram.
module-3
a) Input Unit
b) Memory Unit
c) Control Unit
d) I/O Unit
Answer: c
Explanation: The control unit manages and coordinates the operations of a computer system. The ALU is responsible for performing all the arithmetic and bitwise operations . Therefore, both these units combine to form the brain of the computer ,which is the central processing unit.

24. The part of a processor which contains hardware necessary to perform all the operations required by a computer:
a) Data path
b) Controller
c) Registers
d) Cache
Answer: a
Explanation: A processor is a part of the computer which does all the data manipulation and decision making. A processor comprises of:
A data path which contains the hardware necessary to perform all the operations. A controller tells the data path what needs to be done.
The registers act as intermediate storage for the data.

25. What does MAR stand for?
a) Main Address Register
b) Memory Access Register
c) Main Accessible Register
d) Memory Address Register
Answer: d
Explanation: MAR is a type of register which is responsible for the fetch operation. MAR is connected to the address bus and it specifies the address for the read and write operations.

26. If the control signals are generated by combinational logic, then they are generated by a type of _______________ controlled unit.
a) Micro programmed
b) Software
c) Logic
d) Hardwired
Answer: d
Explanation: The main task of a control unit is to generate control signals. There are two main types of control units:
A hardwired control unit generates control signals by using combinational logic circuits and the Micro programmed control unit generates control signals by using some softwares.

27. Which is the simplest method of implementing hardwired control unit?
a) State Table Method
b) Delay Element Method
c) Sequence Counter Method
d) Using Circuits
Answer: a
Explanation: There are 3 ways of implementing hardwired control unit:
A state table is the simplest method in which a number of circuits are designed based on the cells in the table.
A delay element method consists of a flowchart drawn for the circuit. A D-flip flop is used as a delay element.
A sequence counter method used k-modulo counter as a replacement for k delay elements.

28. A set of microinstructions for a single machine instruction is called ___________
a) Program
b) Command
c) Micro program
d) Micro command
Answer: c
Explanation: For every micro-operation, a set of microinstructions are written which indicate the control signals to be activated. A set of microinstructions is a micro program. The address of the next microinstruction is given by a Micro-program counter.

29. Micro-program consists of a set of microinstructions which are strings of 0s and 1s.
a) True
b) False
Answer: a
Explanation: The computer understands only binary language. So, the micro-program should have instructions which are in the form of 0s and 1s. Each output line of the micro-program corresponds to one control signal.

30. A decoder is required in case of a ______________
a) Vertical Microinstruction
b) Horizontal Microinstruction
c) Multilevel Microinstruction
d) All types of microinstructions
Answer: a
Explanation: There are two types of microinstructions: Horizontal and Vertical.
In a horizontal microinstruction, each bit represents a signal to be activated whereas, in case of vertical microinstruction bits are decoded and, the decoder then produces signals.

31. ________ are the different type/s of generating control signals.
a) Micro-programmed
b) Hardwired
c) Micro-instruction
d) Both Micro-programmed and Hardwired
Answer: d
Explanation: The above is used to generate control signals in different types of system architectures.

32. The type of control signal is generated based on ________
a) contents of the step counter
b) Contents of IR
c) Contents of condition flags
d) All of the mentioned
Answer: d
Explanation: Based on the information above the type of control signal is decided.

33. What does the hardwired control generator consist of?
a) Decoder/encoder
b) Condition codes
c) Control step counter
d) All of the mentioned
Answer: d
Explanation: The CU uses the above blocks and IR to produce the necessary signal.

34. What does the end instruction do?
a) It ends the generation of a signal
b) It ends the complete generation process
c) It starts a new instruction fetch cycle and resets the counter
d) It is used to shift the control to the processor
Answer: c
Explanation: It is basically used to start the generation of a new signal.

35. The Zin signal to the processor is generated using, Zin = T1+T6 ADD + T4.BR…
a) True
b) False
Answer: a
Explanation: The signal is generated using the logic of the formula above.

36. What does the RUN signal do?
a) It causes the termination of a signal
b) It causes a particular signal to perform its operation
c) It causes a particular signal to end
d) It increments the step counter by one
Answer: d
Explanation: The RUN signal increments the step counter by one for each clock cycle.

37. The name hardwired came because the sequence of operations carried out is determined by the wiring.
a) True
b) False
Answer: a
Explanation: In other words hardwired is another name for Hardware Control signal generator.

38. The benefit of using this approach is ________
a) It is cost effective
b) It is highly efficient
c) It is very reliable
d) It increases the speed of operation
Answer: d
Explanation: None.

39. The disadvantage/s of the hardwired approach is ________
a) It is less flexible
b) It cannot be used for complex instructions
c) It is costly
d) less flexible & cannot be used for complex instructions
Answer: d
Explanation: The more complex the instruction set less applicable to a hardwired approach.

40. The End signal is generated using, End = T7.ADD + T5.BR + (T5.N+ T4.-N).BRN…
a) True
b) False
Answer: a
Explanation: None.

41. ______ have been developed specifically for pipelined systems.
a) Utility software
b) Speed up utilities
c) Optimizing compilers
d) None of the mentioned
Answer: c
Explanation: The compilers which are designed to remove redundant parts of the code are called as optimizing compilers.

42. The pipelining process is also called as ______
a) Superscalar operation
b) Assembly line operation
c) Von Neumann cycle
d) None of the mentioned
Answer: b
Explanation: It is called so because it performs its operation at the assembly level.

43. The fetch and execution cycles are interleaved with the help of ________
a) Modification in processor architecture
b) Clock
c) Special unit
d) Control unit
Answer: b
Explanation: The time cycle of the clock is adjusted to perform the interleaving.

44. Each stage in pipelining should be completed within ___________ cycle.
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: The stages in the pipelining should get completed within one cycle to increase the speed of performance.

45. In pipelining the task which requires the least time is performed first.
a) True
b) False
Answer: b
Explanation: This is done to avoid starvation of the longer task.

46. If a unit completes its task before the allotted time period, then _______
a) It’ll perform some other task in the remaining time
b) Its time gets reallocated to a different task
c) It’ll remain idle for the remaining time
d) None of the mentioned
Answer: c
Explanation: None.

47. To increase the speed of memory access in pipelining, we make use of _______
a) Special memory locations
b) Special purpose registers
c) Cache
d) Buffers
Answer: c
Explanation: By using the cache we can reduce the speed of memory access by a factor of 10.

48. The periods of time when the unit is idle is called as _____
a) Stalls
b) Bubbles
c) Hazards
d) Both Stalls and Bubbles
Answer: d
Explanation: The stalls are a type of hazards that affect a pipelined system.

49. The contention for the usage of a hardware device is called ______
a) Structural hazard
b) Stalk
c) Deadlock
d) None of the mentioned
Answer: a
Explanation: None.

50. The situation wherein the data of operands are not available is called ______
a) Data hazard
b) Stock
c) Deadlock
d) Structural hazard
Answer: a
Explanation: Data hazards are generally caused when the data is not ready on the destination side.

Module 4

1.Perform binary addition of 1101 + 0010 is ________
a) 1110
b) 1111
c) 0111
d) 1,1101
Answer: b
Explanation: The addition is performed as :
1101
+ 0010
_______
1111
Therefore, the result is 1111.

2.The addition 1+1 gives 0 as a result.
a) True
b) False
Answer: a
Explanation: The two result obtained is 0 with a carry of 1. This carry is transferred to the next higher column.

3. The result of 0*1 in binary is ____________
a) 0
b) 1
c) invalid
d) 10
Answer: a
Explanation: The binary multiplication of any number with 0 will give the result 0 itself. Any binary number when multiplied by 0 gives 0 only. e.g. 1101 * 0000 = 0000.

4.The multiplication of 110 * 111 is performed. What is a general term used for 111?
a) Dividend
b) Quotient
c) Multiplicand
d) Multiplier
Answer: d
Explanation: 111 is called the multiplier.
Whenever a multiplication is performed the second term is called the multiplier whereas the first term is called the multiplicand.

5.The result obtained on binary multiplication of 1010 * 1100 is _____________
a) 0001111
b) 0011111
c) 1111100
d) 1111000
Answer: d
Explanation: The solution is as follows :
  1010
*  1100
________

     0000
    0000
  1010
1010
_______
1111000

6. Which of the following is often called the double precision format?
a) 64-bit
b) 8-bit
c) 32-bit
d) 128-bit
Answer: a
Explanation: The 64-bit format is referred to as the double precision format. It has 1 sign bit, 8 exponent bits and 23 bits for the mantissa.

7.What do you call the intermediate terms in binary multiplication?
a) Multipliers
b) Mid terms
c) Partial Products
d) Multiplicands
Answer: c
Explanation: The intermediate terms are called partial terms. The mid terms obtained in the binary multiplications are the partial ones whereas the answer obtained is called the final product.

8.The result that is smaller than the smallest number obtained is referred to as ___________
a) NaN
b) Underflow
c) Smallest
d) Mantissa
Answer: b
Explanation: It is referred to as underflow. Nan stands for not a number. Mantissa is the part after the decimal.

9.The number of sign bits in a 32-bit IEEE format is _______
a) 1
b) 11
c) 9
d) 23
Answer: a
Explanation: There is only 1 sign bit in all the standards. In a 32-bit format, there is 1 sign bit, 8 bits for the exponent and 23 bits for the mantissa.

10.Express the decimal format of the signed binary number (101010)2 .
a) 10
b) 12
c) -12
d) -10
Answer: d
Explanation: The first bit is the sign bit whereas the rest of the bits are magnitude bits. So the number is: 01010 =23 * 1 + 21 * 1 =8+2 =10.
But , the sign bit is 1,
Therefore the answer is : (-2)10.

11.__________________ is a straightforward method of representing positive and negative numbers.
a) Radix
b) Complement
c) Sign Magnitude
d) Encode
Answer: c
Explanation: Sign Magnitude is used for the representation of positive and negative numbers. If the leftmost digit is 0, the number is positive. If the leftmost digit is 1, the number is negative.

12.The additive inverse of a number is the number which when added to the original number gives 1 as a result.
a) True
b) False
Answer: b
Explanation: Additive Inverse of a number is the number which gives 0 and not 1 when added to the original number. e.g. number=45, additive inverse =-45, after addition they give 0.

13.The 1’s complement of 1 in 4 bits is __________
a) 0001
b) 0
c) 1001
d) 1110
Answer: d
Explanation: 1’s complement is obtained by reversing the bits from 0 to 1 and vice-versa. Binary of 1 is : 0001 and 1’s complement is : 1110.

14.The binary number 111 in its 2’s complement form is ____________
a) 010
b) 001
c) 000
d) 111
Answer: b
Explanation: 2’s complement is obtained by adding 1 to the 1’s complement. 1’s complement of 111: 000 and 2’s complement:001.

15. The sign magnitude representation of -9 is ___________
a) 00001001
b) 11111001
c) 10001001
d) 11001
Answer: c
Explanation: In case of a negative number, the leftmost digit is 1 if the number is negative. Therefore, +9=00001001 and -9=10001001. Similarly for all other negative numbers.

16.If you are given a word of size n bits, the range of 2’s complement of binary numbers is ________
a) -2n+1 to +2n+1
b) -2n-1 to +2n-1
c) -2n-1 to +2n+1
d) -2n-1 to +2n-1-1
Answer: d
Explanation: 2’s complement is obtained by adding 1 to the 1’s complement. For e.g. 5 :0101 and 1’s complement=1010 and 2’s complement=1011.

17.In both signed magnitude and 2’s complement , positive and negative numbers are separated using ______________
a) LSB
b) MSB
c) 0
d) 1
Answer: b
Explanation: The positive and negative numbers are separated using the MSB. MSB is the Most Significant Bit. MSB is the leftmost bit. e.g. If 1000 is the number then 1 is the most significant bit.

18.Single Precision format comprises of _________ bits.
a) 4
b) 8
c) 16
d) 32
Answer: d
Explanation: The single precision format comprises of 32-bits. It has 1 sign bit, 8 bits for exponent and 23 for the mantissa.

19.If m is the 2’s complement and n is the binary number, then ______________
a) m=n’
b) m=n’+1
c) m=n’-1
d) m=n
Answer: b
Explanation: 2’s complement is simply obtained by addition of 1. So if n is the number and we take the 2’s complement, add 1 to it, we get the 2’s complement. Therefore, m=n’+1.

20.The possible number of bit patterns with 8 bits ________________
a) 128
b) 8
c) 24
d) 256
Answer: d
Explanation: The total number of patterns that can be formed using n-bits are 2n. Here, possible patterns are: 28=256.

21.Which of the following is used for binary multiplication?
a) Restoring Multiplication
b) Booth’s Algorithm
c) Pascal’s Rule
d) Digit-by-digit multiplication
Answer: b
Explanation: The Booth’s Algorithm is used for the multiplication of binary numbers. It is basically used for the multiplication of 2 signed numbers. This is a very important algorithm in binary arithmetic.

22.One extra bit is added on the left of a binary number, in case of Binary Multiplication using Booth’s Algorithm.
a) True
b) False
Answer: a
Explanation: The statement is true as an extra bit is added when we multiply 2 binary numbers by using Booth’s.
Let us take an example if we multiply 2 * – 3.
The first step is to obtain the binary equivalents.
Hence, 2=10 and -3=01.
Now after adding the extra bit 2=010 and -3=101.
We add 0 in case of positive numbers whereas 1 in negative numbers.

23.The binary number obtained after applying RSC on 11010 will be ___________
a) 11101
b) 10100
c) 01101
d) 01000
Answer: c
Explanation: RSC stands for Right-Shift Circulant. So, whenever the numbers are shifted to the right an extra 0 bit is added to the left. Here, after the right shift of 11010, the number obtained will be 01101.

24.The result of >> of 11001 by 3-bits will be ______________
a) 01000
b) 01111
c) 00011
d) 11111
Answer: a
Explanation: >> is the bitwise left shift operator in binary arithmetic.
Applying >>(left-shift) by 3-bits on the number 11001 will result in 3 zeroes on the right, i.e., 01000.

25.Booth’s Algorithm is applied on _____________
a) decimal numbers
b) binary numbers
c) hexadecimal numbers
d) octal Numbers
Answer: b
Explanation: Booth’s Algorithm is applied only on signed and unsigned binary numbers.
Although, the values of other number systems can be converted to binary, and then the multiplication could be performed.

26.If Booth’s Multiplication is performed on the numbers 22*3, then what is 3 referred to as __________
a) accumulator
b) multiplicand
c) quotient
d) multiplier
Answer: d
Explanation: It is referred to as the multiplier. Multiplier is denoted by Q in booth’s algorithm. 22 is called the multiplicand. These numbers are first converted to their binary equivalents and further the multiplication is performed.

27.What is the default value of accumulator in booth’s multiplication of two 4-bit binary numbers?
a) 0
b) 1
c) 0000
d) 00000
Answer: d
Explanation: The correct answer is d because in case of Booth’s algorithm an extra bit is always added to the binary numbers. The 4-bit binary numbers become 5-bit numbers after adding the extra bit. Accumulator is always assigned 0 bits of the order of the binary numbers whose multiplication is to be performed.

28.What is the value of n in multiplication of 110* 1000?
a) 2
b) 3
c) 4
d) 0
Answer: c
Explanation: In Booth’s, n denotes the number of bits that the higher binary number has when multiplication is performed. Here, since there are 4 bits in 1000, the answer is n=4.

29.What will be the value obtained after multiplication of (-2) * (-3) using Booth’s Algorithm?
a) 6
b) -6
c) -2
d) -3
Answer: a
Explanation: After applying the procedure of Booth’s Algorithm, the value obtained will be 6. Even though the result is obtained in its 2’s complement for but then it is reconverted to its normalized form. Also, the value obtained after decimal multiplication is the same as the value obtained after binary multiplication.

30.What does the data transfer instruction STA stand for?
a) Store Accumulator
b) Send Accumulator
c) Send Action
d) Store Action
Answer: a
Explanation: STA is a data transfer instruction given whenever a value is to be copied on the accumulator. It is used for the fetch operation.

31.What is the 1’s complement of 11010?
a) 11010
b) 11011
c) 00110
d) 00101
Answer: d
Explanation: The 1’s complement of a number is obtained by converting all the 0 bits to 1 and all 1’s to 0’s. Here, 11010 gets converted to 00101.

32.2’s complement is obtained by adding 1 to 1’s complement of a number.
a) True
b) False
Answer: a
Explanation: The statement is true. Let us take an example: Consider the number 110000.
1’s complement of the number is 001111. 2’s complement=001111+1=010000.

33.The 10’s complement of 562 is __________
a) 4
b) 3
c) 7
d) 8
Answer: b
Explanation: 10’s complement is obtained by adding 1 to the 9’s complement of a number.
Here, 9’s complement=999-562=436.
Therefore, 10’s complement=436+1=437.

34.The 9’s complement of 6578 is ___________
a) 1234
b) 3421
c) 3124
d) 3420
Answer: b
Explanation: 9’s complement is obtained by subtracting 9 from each bit of the number.
Here, 9999-6578=3421.
Therefore, the 9’s complement is 3421.

35. >> operator is used to denote _________
a) left shift
b) right shift
c) greater than
d) less than
Answer: b
Explanation: >> operator denotes the right shift in binary arithmetic.
E.g. If we say, >>110 by 2-bits, the value obtained will be 001.
Similarly, << denotes the right shift operator.

36.The subtraction using 1’s complement of 110 – 100 will give the result ___________
a) -011
b) 011
c) 010
d) -010
Answer: c
Explanation: To subtract using 1’s complement: Take the 1’s complement of the 2nd number (here, 011) and add it to the first number. (110+011=1,001).
If the carry is generated, it is added to the result (001+1=010).
If a carry is not generated then it is converted to its 1’s complement form.

37.The result obtained on subtraction using 2’s complement of 1111-0010 will be _________
a) 11101
b) 11011
c) 1101
d) 1011
Answer: c
Explanation: Firstly, the 2’s complement of the 2nd number is obtained.
Then, if carry is generated, it is discarded and the number is positive.
Otherwise, 2’s complement of the result is obtained and the answer is negative.
Here, 1111+1110=1, 1101. Since carry is generated, it is discarded and the answer is positive.

38.The 1’s complement of 1111111110.101 is _______________
a) 1.010
b) 0000000000.010
c) 1111111110.101
d) 1.101
Answer: a
Explanation: The 1’s complement of a number is obtained by reversing the bits with value 1 to 0 and the bits with value 0 to 1. Here, 11111111110.101 gets converted to 000000001.010 in its 1’s complement format.

39.7’s complement of 432 is _________________
a) 432
b) 543
c) 345
d) 777
Answer: c
Explanation: To find the 7’s complement of any number, we simply subtract 7 from each of the bits.
Here, 777-432=345. So, the 7’s complement is 345.

40.The 16’s complement of 74E will be __________
a) 8B2
b) F8B2
c) 2B8
d) 8C2
Answer: b
Explanation: The 16’s complement is obtained by subtracting 16 from each of the bits of that number.
Here, 16’s complement of 074E will be F8B2.

41. Binary addition of 1 + 1 gives the result _____________
a) 0
b) 1
c) 2
d) 10
Answer: a
Explanation: The result obtained is 0 with a carry of 1. This carry obtained is added to the next higher column. Binary system can have only two numbers 0 and 1.

42.4-bit is a valid IEEE- format.
a) True
b) False
Answer: b
Explanation: The two main IEEE formats are 16-bit and 32-bit. No format of 4-bit exists. Further, 8-bit format also exists.
In IEEE format, there are certain bits allotted to sign, exponent and mantissa.

43.The result of 0 – 1 in binary is ______________
a) 0
b) 1
c) 11
d) 10
Answer: b
Explanation: The binary subtraction 0 – 1 gives the result 1. A borrow of 1 is although generated and is removed from the next higher column.

44.The complement of any number can be given by a general term _______________
a) Bn – 1 – N
b) Bn -1 + N
c) Bn +1 – N
d) Bn +1 + N
Answer: a
Explanation: Complement of a number can be given by the term :
C= Bn – 1 – N.
Here,
B= base
n= number of digits
N= the number.

45.The IEEE standard followed by almost all the computers for floating point arithmetic _____
a) IEEE 260
b) IEEE 488
c) IEEE 754
d) IEEE 610
Answer: c
Explanation: Most computers follow the IEEE 754 bit format for floating point arithmetic. IEEE stands for electrical and electronic engineers. It has all the floating point arithmetic specifications.

46.Which of the following is often called the double precision format?
a) 64-bit
b) 8-bit
c) 32-bit
d) 128-bit
Answer: a
Explanation: The 64-bit format is referred to as the double precision format. It has 1 sign bit, 8 exponent bits and 23 bits for the mantissa.

47.What is NaN in IEEE standards?
a) Not arithmetic
b) Not a negation
c) Not a number
d) Not a Node
Answer: c
Explanation: It stands for not a number in IEEE standards. A NaN is obtained whenever a result id indeterminate like whenever anything is divided by 0.

48.The result that is smaller than the smallest number obtained is referred to as ___________
a) NaN
b) Underflow
c) Smallest
d) Mantissa
Answer: b
Explanation: It is referred to as underflow. Nan stands for not a number. The mantissa is the part after the decimal.

49.The number of sign bits in a 32-bit IEEE format _________
a) 1
b) 11
c) 9
d) 23
Answer: a
Explanation: There is only 1 sign bit in all the standards. In a 32-bit format, there is 1 sign bit, 8 bits for the exponent and 23 bits for the mantissa.

50.Express the decimal format of the signed binary number (101010)2 .
a) 10
b) 12
c) -12
d) -10
Answer: d
Explanation: The first bit is the sign bit whereas the rest of the bits are magnitude bits. So the number is: 01010 =23 * 1 + 21 * 1 =8+2 =10.
But, the sign bit is 1 ,
Therefore the answer is : (-2)10.

Module 5

1. Any electronic holding place where data can be stored and retrieved later whenever required is ____________
a) memory
b) drive
c) disk
d) circuit

Answer: a
Explanation: Memory is the place where data can be stored and later retrieved. Memory can be of classified into register, cache, main memory, etc.

 

2. Cache memory is the onboard storage.
a) True
b) False

Answer: a
Explanation: Cache Memory is the memory closest to the CPU. Registers, Cache and the main memory are the means of onboard storage in the computer system.

 

3. Which of the following is the fastest means of memory access for CPU?
a) Registers
b) Cache
c) Main memory
d) Virtual Memory

Answer: a
Explanation: Registers are the fastest means of access for CPU. Registers are the small memory locations which are present closest to the CPU.

 

4. The memory implemented using the semiconductor chips is _________
a) Cache
b) Main
c) Secondary
d) Registers

Answer: b
Explanation: The main memory is implemented using semiconductor chips. Main memory is located on the motherboard. It mainly consists of RAM and small amount of ROM.

 

5. Size of the ________ memory mainly depends on the size of the address bus.
a) Main
b) Virtual
c) Secondary
d) Cache

Answer: a
Explanation: The size of the main memory depends on the size of the address bus of the CPU. The main memory mainly consists of RAM and ROM, where RAM contains the current data and programs and ROM contains permanent programs like BIOS.

 

6. Which of the following is independent of the address bus?
a) Secondary memory
b) Main memory
c) Onboard memory
d) Cache memory

Answer: a
Explanation: The secondary memory is independent of the address bus. It increases the storage space. It is implemented in the form of magnetic storage devices.

 

7. ____________ storage is a system where a robotic arm will connect or disconnect off-line mass storage media according to the computer operating system demands.
a) Secondary
b) Virtual
c) Tertiary
d) Magnetic

Answer: c
Explanation: The tertiary storage is the correct option. It is used in the realms of enterprise storage and scientific computing on large computer systems and business computer networks and is something a typical personal computer never sees firsthand.

 

8. What is the location of the internal registers of CPU?
a) Internal
b) On-chip
c) External
d) Motherboard

Answer: b
Explanation: The internal registers are present on-chip. They are therefore present inside the CPU. L1 cache is also present on-chip inside the CPU.

 

9. MAR stands for ___________
a) Memory address register
b) Main address register
c) Main accessible register
d) Memory accessible register

Answer: a
Explanation: The MAR stands for memory address register. It holds the address of the active memory location.

 

10. If M denotes the number of memory locations and N denotes the word size, then an expression that denotes the storage capacity is ______________
a) M*N
b) M+N
c) 2M+N
d) 2M-N

Answer: a
Explanation: Storage capacity is the product of a number of memory locations that is the number of words and the word size or the number of bits stored per location. Storage capacity should be as large as possible.

 

11. What is the high speed memory between the main memory and the CPU called?
a) Register Memory
b) Cache Memory
c) Storage Memory
d) Virtual Memory

Answer: b
Explanation: It is called the Cache Memory. The cache memory is the high speed memory between the main memory and the CPU.

 

12. Cache Memory is implemented using the DRAM chips.
a) True
b) False

Answer: b
Explanation: The Cache memory is implemented using the SRAM chips and not the DRAM chips. SRAM stands for Static RAM. It is faster and is expensive.

 

13. Whenever the data is found in the cache memory it is called as _________
a) HIT
b) MISS
c) FOUND
d) ERROR

Answer: a
Explanation: Whenever the data is found in the cache memory, it is called as Cache HIT. CPU first checks in the cache memory since it is closest to the CPU.

 

14. LRU stands for ___________
a) Low Rate Usage
b) Least Rate Usage
c) Least Recently Used
d) Low Required Usage

Answer: c
Explanation: LRU stands for Least Recently Used. LRU is a type of replacement policy used by the cache memory.

 

15. When the data at a location in cache is different from the data located in the main memory, the cache is called _____________
a) Unique
b) Inconsistent
c) Variable
d) Fault

Answer: b

Explanation: The cache is said to be inconsistent. Inconsistency must be avoided as it leads to serious data bugs.

 

16. Which of the following is not a write policy to avoid Cache Coherence?
a) Write through
b) Write within
c) Write back
d) Buffered write

Answer: b
Explanation: There is no policy which is called as the write within policy. The other three options are the write policies which are used to avoid cache coherence.

 

17. Which of the following is an efficient method of cache updating?
a) Snoopy writes
b) Write through
c) Write within
d) Buffered write

Answer: a
Explanation: Snoopy writes is the efficient method for updating the cache. In this case, the cache controller snoops or monitors the operations of other bus masters.

 

18. In ____________ mapping, the data can be mapped anywhere in the Cache Memory.
a) Associative
b) Direct
c) Set Associative
d) Indirect

Answer: a
Explanation: This happens in the associative mapping. In this case, a block of data from the main memory can be mapped anywhere in the cache memory.

 

19. The number of sign bits in a 32-bit IEEE format is ____
a) 1
b) 11
c) 9
d) 23

Answer: a
Explanation: There is only 1 sign bit in all the standards. In a 32-bit format, there is 1 sign bit, 8 bits for the exponent and 23 bits for the mantissa.

20. The transfer between CPU and Cache is ______________
a) Block transfer
b) Word transfer
c) Set transfer
d) Associative transfe

Answer: b
Explanation: The transfer is a word transfer. In the memory subsystem, word is transferred over the memory data bus and it typically has a width of a word or half-word.

Module 6

1. The DMA differs from the interrupt mode by __________
a) The involvement of the processor for the operation
b) The method of accessing the I/O devices
c) The amount of data transfer possible
d) None of the mentioned
Answer: d
Explanation: DMA is an approach of performing data transfers in bulk between memory and the external device without the intervention of the processor.

2. The DMA transfers are performed by a control circuit called as __________
a) Device interface
b) DMA controller
c) Data controller
d) Overlooker
Answer: b
Explanation: The Controller performs the functions that would normally be carried out by the processor.

3. In DMA transfers, the required signals and addresses are given by the __________
a) Processor
b) Device drivers
c) DMA controllers
d) The program itself
Answer: c
Explanation: The DMA controller acts as a processor for DMA transfers and overlooks the entire process.

4. After the completion of the DMA transfer, the processor is notified by __________
a) Acknowledge signal
b) Interrupt signal
c) WMFC signal
d) None of the mentioned
Answer: b
Explanation: The controller raises an interrupt signal to notify the processor that the transfer was complete.

5. The DMA controller has _______ registers.
a) 4
b) 2
c) 3
d) 1
Answer: c
Explanation: The Controller uses the registers to store the starting address, word count and the status of the operation.

6. When the R/W bit of the status register of the DMA controller is set to 1.
a) Read operation is performed
b) Write operation is performed
c) Read & Write operation is performed
d) None of the mentioned
Answer: a
Explanation: None.

7. The controller is connected to the ____
a) Processor BUS
b) System BUS
c) External BUS
d) None of the mentioned
Answer: b
Explanation: The controller is directly connected to the system BUS to provide faster transfer of data.

8. Can a single DMA controller perform operations on two different disks simultaneously?
a) True
b) False
Answer: a
Explanation: The DMA controller can perform operations on two different disks if the appropriate details are known.

9. The technique whereby the DMA controller steals the access cycles of the processor to operate is called __________
a) Fast conning
b) Memory Con
c) Cycle stealing
d) Memory stealing
Answer: c
Explanation: The controller takes over the processor’s access cycles and performs memory operations.

10. The technique where the controller is given complete access to main memory is __________
a) Cycle stealing
b) Memory stealing
c) Memory Con
d) Burst mode
Answer: d
Explanation: The controller is given full control of the memory access cycles and can transfer blocks at a faster rate.

11. The controller uses _____ to help with the transfers when handling network interfaces.
a) Input Buffer storage
b) Signal enhancers
c) Bridge circuits
d) All of the mentioned
Answer: a
Explanation: The controller stores the data to transfer in the buffer and then transfers it.

12. To overcome the conflict over the possession of the BUS we use ______
a) Optimizers
b) BUS arbitrators
c) Multiple BUS structure
d) None of the mentioned
Answer: b
Explanation: The BUS arbitrator is used to overcome the contention over the BUS possession.

13. The registers of the controller are ______
a) 64 bits
b) 24 bits
c) 32 bits
d) 16 bits
Answer: c
Explanation: None.

14. When the process requests for a DMA transfer?
a) Then the process is temporarily suspended
b) The process continues execution
c) Another process gets executed
d) process is temporarily suspended & Another process gets executed
Answer: d
Explanation: The process requesting the transfer is paused and the operation is performed, meanwhile another process is run on the processor.

15. The DMA transfer is initiated by _____
a) Processor
b) The process being executed
c) I/O devices
d) OS
Answer: c
Explanation: The transfer can only be initiated by an instruction of a program being executed.

16. In memory-mapped I/O ____________
a) The I/O devices and the memory share the same address space
b) The I/O devices have a separate address space
c) The memory and I/O devices have an associated address space
d) A part of the memory is specifically set aside for the I/O operation
Answer: a
Explanation: Its the different modes of accessing the i/o devices.

17. The usual BUS structure used to connect the I/O devices is ___________
a) Star BUS structure
b) Multiple BUS structure
c) Single BUS structure
d) Node to Node BUS structure
Answer: c
Explanation: BUS is a collection of address, control and data lines used to connect the various devices of the computer.

18. In intel’s IA-32 architecture there is a separate 16 bit address space for the I/O devices.
a) False
b) True
Answer: b
Explanation: This type of access is called as I/O mapped devices.

19. The advantage of I/O mapped devices to memory mapped is ___________
a) The former offers faster transfer of data
b) The devices connected using I/O mapping have a bigger buffer space
c) The devices have to deal with fewer address lines
d) No advantage as such
Answer: c
Explanation: Since the I/O mapped devices have a separate address space the address lines are limited by the amount of the space allocated.

20. The system is notified of a read or write operation by ___________
a) Appending an extra bit of the address
b) Enabling the read or write bits of the devices
c) Raising an appropriate interrupt signal
d) Sending a special signal along the BUS
Answer: d
Explanation: It is necessary for the processor to send a signal intimating the request as either read or write.

21. To overcome the lag in the operating speeds of the I/O device and the processor we use ___________
a) BUffer spaces
b) Status flags
c) Interrupt signals
d) Exceptions
Answer: b
Explanation: The processor operating is much faster than that of the I/O devices, so by using the status flags the processor need not wait till the I/O operation is done. It can continue with its work until the status flag is set.

22.The method of accessing the I/O devices by repeatedly checking the status flags is ___________
a) Program-controlled I/O
b) Memory-mapped I/O
c) I/O mapped
d) None of the mentioned
Answer: a
Explanation: In this method, the processor constantly checks the status flags, and when it finds that the flag is set it performs the appropriate operation.

23. The method of synchronising the processor with the I/O device in which the device sends a signal when it is ready is?
a) Exceptions
b) Signal handling
c) Interrupts
d) DMA
Answer: c
Explanation: This is a method of accessing the I/O devices which gives the complete power to the devices, enabling them to intimate the processor when they’re ready for transfer.

24. The method which offers higher speeds of I/O transfers is ___________
a) Interrupts
b) Memory mapping
c) Program-controlled I/O
d) DMA
Answer: d
Explanation: In DMA the I/O devices are directly allowed to interact with the memory without the intervention of the processor and the transfers take place in the form of blocks increasing the speed of operation.

25. The process wherein the processor constantly checks the status flags is called as ___________
a) Polling
b) Inspection
c) Reviewing
d) Echoing
Answer: a
Explanation: None.

26. The interrupt-request line is a part of the ___________
a) Data line
b) Control line
c) Address line
d) None of the mentioned
Answer: b
Explanation: The Interrupt-request line is a control line along which the device is allowed to send the interrupt signal.

27. The return address from the interrupt-service routine is stored on the ___________
a) System heap
b) Processor register
c) Processor stack
d) Memory
Answer: c
Explanation: The Processor after servicing the interrupts as to load the address of the previous process and this address is stored in the stack.

28. The signal sent to the device from the processor to the device after receiving an interrupt is ___________
a) Interrupt-acknowledge
b) Return signal
c) Service signal
d) Permission signal
Answer: a
Explanation: The Processor upon receiving the interrupt should let the device know that its request is received.

29.When the process is returned after an interrupt service ______ should be loaded again.
i) Register contents
ii) Condition codes
iii) Stack contents
iv) Return addresses
a) i, iv
b) ii, iii and iv
c) iii, iv
d) i, ii
Answer: d
Explanation: None.

30. The time between the receiver of an interrupt and its service is ______
a) Interrupt delay
b) Interrupt latency
c) Cycle time
d) Switching time
Answer: b
Explanation: The delay in servicing of an interrupt happens due to the time is taken for contact switch to take place.

31. Interrupts form an important part of _____ systems.
a) Batch processing
b) Multitasking
c) Real-time processing
d) Multi-user
Answer: c
Explanation: This forms an important part of the Real time system since if a process arrives with greater priority then it raises an interrupt and the other process is stopped and the interrupt will be serviced.

32. A single Interrupt line can be used to service n different devices.
a) True
b) False
Answer: a
Explanation: None.

33. ______ type circuits are generally used for interrupt service lines.
i) open-collector
ii) open-drain
iii) XOR
iv) XNOR
a) i, ii
b) ii
c) ii, iii
d) ii, iv
Answer: a
Explanation: None.

34.The resistor which is attached to the service line is called _____
a) Push-down resistor
b) Pull-up resistor
c) Break down resistor
d) Line resistor
Answer: b
Explanation: This resistor is used to pull up the voltage of the interrupt service line.

35. An interrupt that can be temporarily ignored is ___________
a) Vectored interrupt
b) Non-maskable interrupt
c) Maskable interrupt
d) High priority interrupt
Answer: c
Explanation: The maskable interrupts are usually low priority interrupts which can be ignored if a higher priority process is being executed.

36. The 8085 microprocessor responds to the presence of an interrupt ___________
a) As soon as the trap pin becomes ‘LOW’
b) By checking the trap pin for ‘high’ status at the end of each instruction fetch
c) By checking the trap pin for ‘high’ status at the end of execution of each instruction
d) By checking the trap pin for ‘high’ status at regular intervals
Answer: c
Explanation: The 8085 microprocessor are designed to complete the execution of the current instruction and then to service the interrupts.

37. CPU as two modes privileged and non-privileged. In order to change the mode from privileged to non-privileged.
a) A hardware interrupt is needed
b) A software interrupt is needed
c) Either hardware or software interrupt is needed
d) A non-privileged instruction (which does not generate an interrupt)is needed
Answer: b
Explanation: A software interrupt by some program which needs some CPU service, at that time the two modes can be interchanged.

38. Which interrupt is unmaskable?
a) RST 5.5
b) RST 7.5
c) TRAP
d) Both RST 5.5 and 7.5
Answer: c
Explanation: The trap is a non-maskable interrupt as it deals with the ongoing process in the processor. The trap is initiated by the process being executed due to lack of data required for its completion. Hence trap is unmaskable.

39. From amongst the following given scenarios determine the right one to justify interrupt mode of data transfer.
i) Bulk transfer of several kilo-byte
ii) Moderately large data transfer of more than 1kb
iii) Short events like mouse action
iv) Keyboard inputs
a) i and ii
b) ii
c) i, ii and iv
d) iv
Answer: d
Explanation: None.

40.How can the processor ignore other interrupts when it is servicing one ___________
a) By turning off the interrupt request line
b) By disabling the devices from sending the interrupts
c) BY using edge-triggered request lines
d) All of the mentioned
Answer: d
Explanation: None.

41. When dealing with multiple devices interrupts, which mechanism is easy to implement?
a) Polling method
b) Vectored interrupts
c) Interrupt nesting
d) None of the mentioned
Answer: a
Explanation: In this method, the processor checks the IRQ bits of all the devices, whichever is enabled first that device is serviced.

42. The interrupt servicing mechanism in which the requesting device identifies itself to the processor to be serviced is ___________
a) Polling
b) Vectored interrupts
c) Interrupt nesting
d) Simultaneous requesting
Answer: b
Explanation: None.

43. In vectored interrupts, how does the device identify itself to the processor?
a) By sending its device id
b) By sending the machine code for the interrupt service routine
c) By sending the starting address of the service routine
d) None of the mentioned
Answer: c
Explanation: By sending the starting address of the routine the device ids the routine required and thereby identifying itself.

44. The code sent by the device in vectored interrupt is _____ long.
a) upto 16 bits
b) upto 32 bits
c) upto 24 bits
d) 4-8 bits
Answer: d
Explanation: None.

45. The starting address sent by the device in vectored interrupt is called as __________
a) Location id
b) Interrupt vector
c) Service location
d) Service id
Answer: b
Explanation: None.

46. The processor indicates to the devices that it is ready to receive interrupts ________
a) By enabling the interrupt request line
b) By enabling the IRQ bits
c) By activating the interrupt acknowledge line
d) None of the mentioned
Answer: c
Explanation: When the processor activates the acknowledge line the devices send their interrupts to the processor.

47. We describe a protocol of input device communication below:
i) Each device has a distinct address.
ii) The BUS controller scans each device in a sequence of increasing address value to determine if the entity wishes to communicate
iii) The device ready to communicate leaves its data in the I/O register
iv) The data is picked up and the controller moves to the step a
Identify the form of communication best describes the I/O mode amongst the following.
a) Programmed mode of data transfer
b) DMA
c) Interrupt mode
d) Polling
Answer: d
Explanation: In polling, the processor checks each of the devices if they wish to perform data transfer and if they do it performs the particular operation.

48. Which one of the following is true with regard to a CPU having a single interrupt request line and single interrupt grant line?
i) Neither vectored nor multiple interrupting devices is possible.
ii) Vectored interrupts is not possible but multiple interrupting devices is possible.
iii) Vectored interrupts is possible and multiple interrupting devices is not possible.
iv) Both vectored and multiple interrupting devices are possible.
a) iii
b) i, iv
c) ii, iii
d) iii, iv
Answer: a
Explanation: None.

49. Which table handle stores the addresses of the interrupt handling sub-routines?
a) Interrupt-vector table
b) Vector table
c) Symbol link table
d) None of the mentioned
Answer: a
Explanation: None.

50. _________ method is used to establish priority by serially connecting all devices that request an interrupt.
a) Vectored-interrupting
b) Daisy chain
c) Priority
d) Polling
Answer: b
Explanation: In the Daisy chain mechanism, all the devices are connected using a single request line and they’re serviced based on the interrupting device’s priority.

51. In daisy chaining device 0 will pass the signal only if it has _______
a) Interrupt request
b) No interrupt request
c) Both No interrupt and Interrupt request
d) None of the mentioned
Answer: b
Explanation: In daisy chaining since there is only one request line and only one acknowledges line, the acknowledge signal passes from device to device until the one with the interrupt is found.

52. ______ interrupt method uses register whose bits are set separately by interrupt signal for each device.
a) Parallel priority interrupt
b) Serial priority interrupt
c) Daisy chaining
d) None of the mentioned
Answer: a
Explanation: None.

53. ______________ register is used for the purpose of controlling the status of each interrupt request in parallel priority interrupt.
a) Mass
b) Mark
c) Make
d) Mask
Answer: d
Explanation: None.

54. The added output of the bits of the interrupt register and the mask register is set as an input of ______________
a) Priority decoder
b) Priority encoder
c) Process id encoder
d) Multiplexer
Answer: b
Explanation: In a parallel priority system, the priority of the device is obtained by adding the contents of the interrupt register and the mask register.

55. Interrupts initiated by an instruction is called as _______
a) Internal
b) External
c) Hardware
d) Software
Answer: b
Explanation: None.

56. Input or output devices that are connected to computer are called ______________.
A. Input/Output Subsystem
B. Peripheral Devices
C. Interfaces
D. Interrupt
Ans : B
Explanation: Input or output devices that are connected to computer are called peripheral devices.

57. How many types of modes of I/O Data Transfer?
A. 2
B. 3
C. 4
D. 5
Ans : B
Explanation: Generally three types of modes which are : Programmed I/O, Interrupt Initiated I/O, Direct Memory Access

58. Keyboard and Mouse Comes under?
A. Input peripherals
B. Output peripherals
C. Input-Output peripherals
D. None of the above
Ans : A
Explanation: Allows user input, from the outside world to the computer. Example: Keyboard, Mouse etc.

59.The method which offers higher speeds of I/O transfers is ___________
A. Interrupts
B. Memory mapping
C. Program-controlled I/O
D. DMA
Ans : D
Explanation: In DMA the I/O devices are directly allowed to interact with the memory without the intervention of the processor and the transfers take place in the form of blocks increasing the speed of operation.

60. In memory-mapped I/O ____________
A. The I/O devices have a separate address space
B. The I/O devices and the memory share the same address space
C. A part of the memory is specifically set aside for the I/O operation
D. The memory and I/O devices have an associated address space
Ans : B
Explanation: Its the different modes of accessing the i/o devices.

61. The ________ circuit is basically used to extend the processor BUS to connect devices.
A. Router
B. Router
C. Bridge
D. None of the above
Ans : C
Explanation: The bridge circuit is basically used to extend the processor BUS to connect devices.

62. The ISA is an architectural standard developed by ______.
A. IBM
B. AT&T Labs
C. Microsoft
D. Oracle
Ans : A
Explanation: Industry Standard Architecture is an architectural standard developed by IBM for its PC’s.

63. The SCSI BUS is used to connect the video devices to a processor by providing a ______________.
A. Single Bus
B. USB
C. SCSI
D. parallel BUS.
Ans : D
Explanation: The SCSI BUS is used to connect the video devices to a processor by providing a parallel BUS.

64.Which of the following is true about DMA?
A. DMA is an approach of performing data transfers in bulk between memory and the external device without the intervention of the processor.
B. The DMA controller acts as a processor for DMA transfers and overlooks the entire process.
C. The DMA controller has 3 registers.
D. All of the above
Ans : D
Explanation: all of the above statement is true regarding DMA.

65. The registers of the controller are ______
A. 16 bit
B. 32 bit
C. 64 bit
D. 128 bit
Ans : B
Explanation: The registers of the controller are 32 bit.

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