## [MCQ] Metrology

#### Module 1

1. Which of the following instrument is of the highest accuracy?
a) Digital length gauge
b) Inside micrometer
c) Universal measuring instrument
d) Universal height micrometer
Explanation: Universal measuring instrument is of the highest accuracy due to the presence of sensors, micro switches and microprocessors.

2. Which of the following option is incorrect about the universal measuring instrument?
a) Twin digital display is present
b) Highly skilled operator is required
c) Computation capabilities
d) Automatically sense diameter of bores
Explanation: Twin display is present one in the front and other in the side for easy reading. Low skilled operator is required as it has automatic computation capabilities which eliminate possibilities of operator’s error.

3. Which of the following statement is true for following statements about universal measuring instrument?
Statement 1: Microprocessor and micro switches are present.
Statement 2: Coefficient of thermal expansion of measuring instrument made of steel is the same as a component to be measured.
a) F, T
b) T, T
c) F, F
d) T, F
Explanation: Same coefficient of thermal expansion of measuring instrument and component to be measured hence, there is no effect of temperature variation on measuring accuracy.

4. What is the permissible measuring speed in universal measuring instrument for error free reading?
a) 1 m/sec
b) 1 mm/sec
c) 1 cm/sec
d) 2 cm/sec
Explanation: 1 m/second is the permissible measuring speed for error free reading. These instruments saves inspection time with high accuracy.

5. How many push buttons are needed for convenient and easy operations?
a) 5
b) 6
c) 7
d) 8
Explanation: There are 5 push button keys are present near readout for easy measurement. Functions of these 5 buttons are: selection of measuring program, input of probe constant, changing reference datum, addition and subtraction and zero setting.

6. Which of the following is correct about electronic display unit of universal measuring instrument?
a) Sensitive to electrical interference
b) Non-removable
c) Cast iron protection cover
d) It is plug-in type
Explanation: It is insensitive to electrical interference and oil film. It is easily interchangeable. There is an aluminium protection cover for an electronic display unit.

7. A universal measuring instrument can withstand up to which temperature for correct reading?
a) 100oC
b) 75oC
c) 65oC
d) 50oC
Explanation: Display unit can withstand temperature up to 50oC and 95% relative humidity.

8. Which of the following option is correct for given statements about universal measuring instrument?
Statement 1: There is a rack and pinion movement in measuring slide.
Statement 2: An independent power supply unit is screwed to the base.
a) Only statement 1 is true
b) Only statement 2 is true
c) Both the statements are true
d) Both the statements are not true
Explanation: There is no rack and pinion movement or backlash in EDU. It is completely independent and interchangeable. A power supply unit is screwed with 4 screws to the base.

9. What is the range of voltage fluctuations which can be taken care by an electronic unit in universal measuring instrument?
a) 18% to 20%
b) -10% to +50%
c) -18% to +20%
d) 10% to 50%
Explanation: An interrupted power supply is provided to the electronic unit by power supply unit. It takes cares from – 18 to +20% fluctuations of voltage.

10. Match the following:
Column 1: Part of instrument
Column 2: information regarding a instrument
A) Accessories – 1) Tungsten carbide coating
B) Supporting pads – 2) Balance counter weight
C) Handwheel – 3) Cast iron
D) Base – 4) Built-in microswitch
a) A-2, B-1, C-4, D-3
b) A-1, B-2, C-3, D-4
c) A-3, B-4, C-1, C-2
d) A-4, B-3, C-2, D-1
Explanation: Accessories are designed to balance with the counter weight. 3 supporting pads are present with tungsten carbide coating except at the top which can be lapped. Built-in microswitches are present in hand wheel which compensate automatically for probe constant.

11. What is the least count of a micrometer?
a) 0.01 mm
b) 0.02 mm
c) 0.1 mm
d) 0.2 mm
Explanation: Least count can be calculated by “Pitch divided by no. of divisions on a circular scale”.

12. What is the use of ratchet stop in micrometer?
a) Prevent motion of spindle
b) Maintain uniform measuring pressure
c) Provide measuring surface
d) Forms measuring tip
Explanation: Ratchet stop is present at the end of thimble cap to maintain a uniform measuring pressure. By ratchet stop standard conditions of measurement are attained.

13. Which of the following is incorrect about micrometer?
a) Thimble and barrel should have a dull finish
b) Total travel of the measuring spindle is called measuring range
c) Graduated surface diameter of barrel should be 5 mm
d) Screw has 10 or 20 threads per cm
Explanation: Thimble and barrel should have a dull finish for ease of reading. Graduated surface diameter of the barrel should not be less than 10 mm.

14. What is the hardness of measuring faces of anvil and spindle?
a) 800 HV
b) 600 HV
c) 1000 HV
d) 100 HV
Explanation: Measuring faces of anvil and spindle has a hardness of about 800 HV or 62 HRC. Faces may be tipped with tungsten carbide.

15. What is the total error in micrometer?
a) Positive and negative deviation from the zero point
b) Error in parallelism
c) Deviation from measurement of a nominal dimension
d) Maximum difference between ordinates of cumulative error
Explanation: Cumulative error is the deviation of measurement from a nominal dimension. It includes errors like thread errors, errors of measuring faces etc. Maximum difference between ordinates of cumulative error is the total error.

16. How many divisions are graduated on thimble?
a) 20
b) 25
c) 45
d) 50
Explanation: Graduation lines should be clearly engraved. 50 divisions are graduated on thimble each representing 0.01mm.

17. Which of the following is incorrect for vernier height gauge?
a) Both the surfaces of measuring jaw should be at 45o to the base
b) These gauges can be used for scribing purposes
c) Removable clamps are used
d) Surface plate is used as datum surface for measurements
Explanation: Both surfaces of measuring jaw i.e. upper and lower are parallel to the base. It can be used for measurements under or over a surface. In place of measuring jaw, a scriber can be attached to scribe lines.

18. What is the hardness of measuring jaws of vernier height gauge made up of stainless steel?
a) 350 HV
b) 450 HV
c) 550 HV
d) 650 HV
Explanation: The measuring jaws, scriber and underside of a base are made up of good quality steel and high carbon stainless steel. Hardness of these parts is about 700 and 650 HV for good quality steel and stainless steel respectively.

19. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: The projection of scriber beyond the jaw should be 10 mm.
Statement 2: Flatness of working surface of scriber can be checked by the knife edge.
a) Only statement 1 is correct
b) Only statement 2 is correct
c) Both the statements are correct
d) Both the statements are incorrect
Explanation: The scriber is projected at least 25 mm beyond the jaws. Height gauges may also have an offset scriber. Flatness of working surfaces of scriber and measuring jaws is checked by knife edge straight edge or optical flats.

20. What is the standard reference temperature for the measurement of the accuracy of vernier height gauges?
a) 20 K
b) 20oC
c) 40 K
d) 40oC
Explanation: Temperature of 20oC should be maintained in the room where the test is conducted. A height gauge should rest on a precision surface plate to increase the testing accuracy.

21. Which of the following option is correct for the given statements about vernier height gauge?
Statement 1: Surface of the vernier and beam should have a dull finish.
Statement 2: Springing of measuring jaws is desirable.
a) T, F
b) F, F
c) T, T
d) F, T
Explanation: Surfaces of vernier and beam have a dull finish for easy readings. A magnifying lens is also provided for this purpose. A proper care of vernier height gauges is very important. Springing of jaws is always avoided.

22. Which of the following is used for checking the perpendicular distance from the graduated face of a beam to the graduated face of vernier?
a) Angle gauge
b) Vernier depth gauge
c) Feeler gauge
d) Slip gauge
Explanation: It is measured with a 0.1 mm feeler gauge. Vernier depth gauges are used to measure the depth of holes and recesses.

23. Vernier is at which position when the scriber is coplanar with the base?
a) Vernier is exactly at the middle position of the scale
b) Vernier reads 1/4th of the scale
c) Vernier is at 3/4th position
Explanation: Scale on the beam is positioned in the manner that vernier reads zero when scriber and base are coplanar. In case of wear, some adjustments are made to reset zero position.

#### Module 2

1. What are the functional dimensions?
a) Have to be machined and fit with other mating components
b) Which have no effect on the performance of quality
c) Need not to be machined to an accuracy of the high degree
d) Function is more important than accuracy
Explanation: Non-functional dimensions have no effect on the performance of quality of the assembly or component. Non-functional dimensions need not to be machined to higher accuracy.

2. Why tolerances are given to the parts?
a) Because it’s impossible to make perfect settings
b) To reduce weight of the component
c) To reduce cost of the assembly
d) To reduce amount of material used
Explanation: Tolerances are provided to the parts because variations in the material properties introduce errors and production machines themselves have inherent inaccuracies. Another reason to introduce tolerance is that it is not possible to make perfect settings by operator so some tolerances are provided.

3. What is bilateral tolerance?
a) Total tolerance is in 1 direction only
b) Total tolerance is in both the directions
c) May or may not be in one direction
d) Tolerance provided all over the component body
Explanation: Total tolerance is specified on both the sides of the basic dimension. This usually have + and – tolerance of equal amount.

4. Which type of tolerance provided in drilling mostly?
a) Bilateral
b) Unilateral
c) Trilateral
d) Compound
Explanation: Mostly unilateral tolerance is provided in drilling as dimension is allowed to vary in one direction only. Hole is always oversize, not undersize.

5. What is mean clearance?
a) Maximum size of hole minus maximum size of shaft
b) Minimum size of hole minus minimum size of shaft
c) Mean size of hole minus mean size of shaft
d) Average of both size of shaft and hole
Explanation: Statistical approach allows wider tolerances compared to complete interchangeability approach. Methods used by statistical approach are usually permits cheaper production. Mean clearance is equal to (mean size of hole – mean size of shaft).

6. Which of the following is incorrect about tolerances?
a) Too loose tolerance results in less cost
b) Tolerance is a compromise between accuracy and ability
c) Too tight tolerance may result in excessive cost
d) Fit between mating components is decided by functional requirements
Explanation: Loose tolerance results in increase in cost, assembly problems and poor performance of the product. Tight tolerance results in unnecessary machining and inspection time.

7. Which of the following is the incorrect condition for a perfectly flat surface when tested for interferometry?
a) Monochromatic light is used
b) Viewing angle should be greater than 0o
c) Optical flats are important in light wave measurement
d) For perfect flat surface alternate light and dark bands are observed
Explanation: Angle at which bands are viewed is called viewing angle. Viewing angle should be 0o that is line of sight should be at 90 degrees to the reference surface of optical flats. As this angle increases it will cause error.

8. If the angle at which bands are viewed is 30o in flatness testing with interferometry, what is the possible error?
a) 0%
b) 15%
c) 30%
d) 45%
Explanation: If the viewing angle is 30 degrees then three fringes may be seen as 2.5 that is it will cause error of 15 %. If the viewing angle is 45 degrees then three fringes may be seen as 1.75 that is it will cause nearly 40% error.

9. What is the range of the diameter of optical flats?
a) 10 to 50 mm
b) 50 to 100 mm
c) 100 to 200 mm
d) 25 to 300 mm
Explanation: Optical flats are the circular pieces of optical glass with a high degree of finish on the working surfaces. Its two plane faces are flat and parallel to each other. Optical flats varies from the size of 25 to 300 mm.

10. In flatness testing with interferometry, if surfaces are perfectly wrung. Then which option is correct regarding fringe pattern?
a) No fringe pattern
b) Fringes are closer
c) Fringes are at great distance
d) Indistinguishable pattern
Explanation: If the surface between optical flat and work surface are perfectly wrung together then there will be no air gap between the surfaces and fringe pattern will be not observable.

11. Which of the following is true for quartz flats?
a) Have 200 to 400 % more wearing quality than optical flats
b) Have 10 % more wearing quality than optical flats
c) Have 10 % less wearing quality than optical flats
d) Have 200 to 400 % less wearing quality than optical flats
Explanation: Quartz flats have more wearing qualities than optical flats. It is 200 to 400 percent more than optical flats. Working surfaces are finished to a high optical degree of flatness.

12. Which principle is related to Gauge design?
a) Rankin principle
b) Position principle
c) Taylor’s principle
d) Carnot Principle
Explanation: According to Taylor’s principle, “‘No Go’ and ‘Go’ gauges are designed to check the minimum and maximum material limits”. In gauge design, simplicity is the main aim as simple gauge can take measurements accurately and continuously.

13. ‘Go limit’ applied to which limit condition?
a) Maximum material limit
b) Minimum material limit
c) Lower limit of shaft and upper limit of hole
d) Moderate material limit
Explanation: ‘Go’ limit is applied to the limit corresponds to maximum material limit condition that is lower limit of hole and upper limit of shaft while ‘No Go’ limit is applied to minimum material condition that is upper limit of a hole and lower limit of a shaft.

14. Which of the following is true for plug gauges?
a) Size difference between ‘Go’ and ‘No Go’ plug gauges is greater than the tolerance of tested shaft or hole
b) Size difference between ‘Go’ and ‘No Go’ plug gauges is Equal to the tolerance of tested shaft or hole
c) Size difference between ‘Go’ and ‘No Go’ plug gauges is less than the tolerance of tested shaft or hole
d) Size difference between ‘Go’ and ‘No Go’ plug gauges more or less than the tolerance of tested shaft or hole
Explanation: In case of standard gauges, size difference between ‘Go’ and ‘No Go’ plug and snap gauges is equal to tolerance. To maintain size and adequate functioning of snap gauges, robustness and rigidity are the main features.

15. Which of the following is incorrect for the gauging faces of snap gauges?
a) Parallel to each other
b) Square to each other
c) Gauging point and work are in same plane
d) Work and gauging faces are at 60 degree
Explanation: Gauging faces of a gap and snap gauges are square and parallel to each other. If gauging diameter of component is larger than gap setting then it will produce welding action may lead to distortion in gauge are incorrect interpretation of reading.

16. Which of the following can’t be done by ‘Go’ plug gauges?
a) Ensure bore alignability
b) Controls diameter
c) Check straightness of hole
d) Check degree of ovality
Explanation: ‘Go’ plug gauge is preferably full length of hole hence straightness can be checked. ‘Go’ gauges can’t check degree of ovality. ‘No Go’ plug gauges are short and its function depends on the diameter and circularity of hole.

17. Which of the following is true for uses of comparators?
a) Can’t be used in mass production
b) Not suitable for inspection purposes
c) Can be used as working gauge
d) Slow rate of working
Explanation: Comparators are used in mass production where components are checked at a fast rate. These can be used as inspection purposes, laboratory standards and working standards or gauges.

18. What is the principle of ‘The Johansson Mikrokator’?
a) Button spinning on a loop of string
b) Principle of interference
c) Optical magnification
d) Principle of transformer
Explanation: Johansson Mikrokator is a mechanical comparator used to obtain mechanical magnification. Principle of Johansson Mikrokator is ‘spinning of a button on a loop string’. Magnification of this comparator is of the order of 5000.

19. From which category ‘Sigma comparator’ belongs?
a) Optical comparator
b) Mechanical comparator
c) Mechanical-optical comparator
d) Pneumatic comparator
Explanation: Sigma comparator is a mechanical comparator. Components of sigma comparator are a plunger, knife edge, cross strip hinge, Y-shaped arm, driving drum, slit diaphragm, a scale and a pointer etc.

20. What is the advantage of mechanical comparator over others?
a) Less moving parts
b) No need of external supply
c) No error due to parallax
d) Large range of instrument
Explanation: Mechanical comparator is cheaper as compared to others. Mechanical comparators have more moving parts due to this friction is more and accuracy is less. External supply is not required. Moving pointer moves over a fixed scale hence error due to parallax is possible.

21. Which of the following is true for ’Cross strip’ in sigma comparator?
a) Has two moving members
b) Cross strip is hinged
c) Two members are at 45o to each other
d) A flexible strip is attached to any one of the members of cross strip
Explanation: A hinged cross strip is present in sigma comparator which has a fixed and a

22. Which of the following is not correct for pneumatic comparator?
a) Independent of operator skill
b) Loss of accuracy due to gauge wear
c) Speedy operation
d) Total life cost is less
Explanation: In pneumatic comparator, there is no physical contact with setting gauge or part being measured. Due to this reason, there is no loss of accuracy due to gauge wear. It is an accurate, universal, reliable and speedy device.

23. What is the order of magnification in flow type pneumatic gauge?
a) 100 to 1000 times
b) 500 to 5000 times
c) 50 to 500 times
d) 100 to 2000 times
Explanation: Velocity type pneumatic gauge have quick response. It can permit a large clearance between object surface and nozzle which results in less wear in gauging members. Less air consumption. So, the magnification of the order to 500-5000 times is possible.

24. Which of the following is true for Pneumatic sensitivity in pneumatic comparators?
a) Directly proportional to operating pressure
b) Inversely proportion to operating pressure
c) Directly proportional to geometrical area of orifice
d) Independent of area of orifice and operating pressure
Explanation: Pneumatic sensitivity in the pneumatic comparator is directly dependent upon the operating pressure and inversely proportional to the geometrical area of the orifice. It can be represented as dp/dM.

25. What is the formula for overall magnification of pneumatic comparator? (Where, λ is the length of scale of pressure measuring device and La is the average separation between nozzle surface and surface to be gauged)
a) 0.4*λ/La
b) 0.7*λ/La
c) 0.4*λ*La
d) 0.7*λ*La
Explanation: Overall magnification depends upon pneumatic sensitivity, sensitivity of pressure measuring device that is rate of change of reading w.r.t. varying pressure and upon rate of change of geometrical area of orifice w.r.t. ‘L’.

26. What is the relation between overall magnification and pneumatic sensitivity in pneumatic comparators?
a) Independent of each other
b) Overall magnification is directly dependent on the square of pneumatic sensitivity
c) Overall magnification is inversely proportional to the pneumatic sensitivity
d) Overall magnification is directly dependent on the pneumatic sensitivity
Explanation: Overall magnification is the rate of change of linear movement of the pointer to the change in the dimension which produces it and represented as dR/dL. It is directly proportional to the pneumatic sensitivity.

27. What is the importance of the valley in any irregular surface?
a) Reduce metal to metal contact
b) Retain film of lubricating oil
c) Reduce stress concentration
d) Improve surface texture
Explanation: The hills in any irregular surface helps in reducing metal to metal contact and valleys are useful to retain the film of lubricating oil on the surface otherwise it will be difficult to maintain lubricating oil film on the surface.

28. What is the relation between rate of wear and contact surface area?
a) Rate of wear is inversely proportional to the contact surface area
b) Rate of wear is directly proportional to the contact surface area
c) Rate of wear is inversely proportional to the square of contact surface area
d) Rate of wear is directly proportional to the square of contact surface area
Explanation: If any surface has large number of irregularities i.e. hills and valley then the surface will obtain good bearing properties. Rate of wear is proportional to the load per unit area and surface area in contact.

29. Which of the following option is true for given statements about surface texture?
Statement 1: Concept of surface roughness is sensory.
Statement 2: Failure due to fatigue starts always at sharp corners.
a) T, F
b) F, T
c) F, F
d) T, T
Explanation: Concept of a roughness of surface is sensory. Surface roughness has been understood by a sense of touch and light. Failure due to Fatigue starts at sharp corner because at sharp corners stress concentration is more and that part fails earlier.

30. Which of the following is not true about first order irregularities?
a) Arising due to irregularities in machine tool itself
b) Arising due to weight of material itself
c) Arise due to vibrations
d) May arises due to deformation of work under action
Explanation: First order irregularities includes the irregularities arising out of inaccuracies in the machine tool itself. This includes the irregularities on surface arising due to work deformation under the action of cutting forces and the material weight itself.

31. Under which group, does waviness in surface falls?
a) Primary texture
b) Secondary texture
c) Tertiary texture
d) Quaternary texture
Explanation: If the hills and valleys are not close to each other or they both are far apart, it is due to the machine tool imperfections and this is referred to as waviness or secondary texture.

32. What is meant by roughness?
a) Minute succession of hills of different height
b) Minute succession of valleys and hills of different height and varied spacing
c) Minute succession of valleys and hills of same height and same gap
d) Minute succession of valleys of different depth
Explanation: Imperfections are bound to be on surface and they take the form of succession of hills and valleys which vary in height and spacing which result in irregularity of the surface. Roughness is the form of these minute imperfections.

33. Surfaces produced by straight and cylindrical grinding tools tend to create which type of roughness?
a) Regularly spaced but directional roughness
b) Regularly spaced but non directional roughness
c) Irregularly spaced but directional roughness
d) Irregularly spaced but non directional roughness
Explanation: The roughness on the surface tends to be both irregularly spaced and directional in straight and cylindrical grinding and in the case of boring or lapping process the surface roughness tends to be irregular and non-directional in nature.

34. Which of the following is necessary for the complete study of surface roughness?
a) Measurement of all the components of elements
b) Analysis of all the component element
c) Assessment of the effects of combined texture
d) Measurement and analysis of all the components and assessment of combined texture
Explanation: For the complete study of the surface roughness, it is important that the analysis and measurement of all the component elements be made and an assessment of the effects of the combined texture be made.

35. Which of the following is true for measurement of surface roughness?
a) 3 dimensional geometry can be easily measured
b) Direction of measurement is perpendicular to the lay
c) Direction of measurement is parallel to the lay
d) Direction of measurement is parallel to the direction of the predominant surface marking
Explanation: There are difficulties in the measurement of surface roughness in three dimensional geometry, but for simplification purposes, it is reduced into two dimensional geometry. To measure, the direction is generally perpendicular to the direction of the predominant surface markings or “lay”.

36. How much a stylus instrument can be magnified to plot or find minute irregularities?
a) 50 times
b) 500 times
c) 5000 times
d) 50,000 times
Explanation: The shape of the hills and valleys is best studied in a cross-section normal to the surface using a stylus instrument which plots a graph in which even the minute irregularities are magnified upto 50,000 times whereas the length over which observations are made is magnified only by 50-300 times.

37. Which of the following is the best for the examination of surface finish?
a) Touch inspection
b) Visual inspection
c) Scratch inspection
d) Microscopic inspection
Explanation: Microscopic inspection is the best method for examining the surface finish. Visual, touch and scratch inspection methods are not as accurate as microscopic. In these methods, minute flaws can’t be detected.

38. Upto which limits irregularities can be detected with touch inspection of a surface?
a) 0.0001 mm
b) 0.001 mm
c) 0.01 mm
d) 0.1 mm
Explanation: Touch inspection method can tell which surface is rougher. In this method, the finger-tip is moved along the surface at a speed of about 25/sec and the irregularities of about 0.01 mm can be easily detected.

39. Which of the following material is not used for rubbing on the surface to be inspected in scratch inspection?
a) Softer material
b) Hard material
c) Plastic
Explanation: In scratch inspection method, a softer material like plastic or lead babbitt is rubbed over the surface to be inspected. It carries the impression of the scratches on it which can be easily visualised.

40. Which of the following option is true for given statements about method of measurement of surface finish?
Statement 1: Minute flaws can be easily detected by touch inspection.
Statement 2: Direct instrument measurement is enabled to determine a numerical value of surface finish.
a) F, T
b) T, F
c) F, F
d) T, T
Explanation: The main limitation of the method of inspection by touch is that the degree of surface roughness can not be assessed by this and also the minute flaws can’t be detected by the only touch.

41. What is the limitation of microscopic inspection to check surface finish?
a) An average value is needed
b) Small portion of surface can be detected at a time
c) A master finish surface is also needed
d) It is necessary to inspect whole surface together
Explanation: Microscopic inspection method have some limitation that at a time only a small portion of the surface can be inspected. So for inspection, several readings are required in this method to get an average value.

#### Module 3

1. What is the name of screw thread that is formed on a cone?
Explanation: A screw thread is formed by forming a continuous helical groove on the external or internal surface of cylinder. The screw thread formed on frustum of a cone or a cone is called as tapered screw thread.

2. What type of thread is formed on female screw gauge?
c) Both internal and external
Explanation: An internal thread is that which formed on the inside of a workpiece e.g. on female screw gauge or a nut. An external thread is that which formed on the outside of a workpiece e.g on bolts or studs.

3. Which of the following option is true for truncation?
a) Thread can be tranculated at crest only
b) Thread can be tranculatd at root only
c) Thread can be tranculated at crest and root both
d) Thread can’t be tranculated at crest and root both
Explanation: A thread is truncated sometimes at the crest or at the root or at both root and crest and root. The radial distance from the crest to the nearest apex of the fundamental triangle is truncation at the crest is and at the root it is the radial distance from the root to the nearest apex.

4. What is dedendum for external threads?
a) Radial distance between pitch and minor cylinder
b) Radial distance between major and pitch cylinder
c) Radial distance between major and minor cylinder
d) Axial distance between major and pitch cylinder
Explanation: Addendum for an external thread is defined as the radial distance between the major cylinder and pitch cylinder and for internal addendum is the radial distance between the minor cylinder and pitch cylinder. Dedendum for external thread is the radial distance between the pitch cylinder and minor cylinder and this is the radial distance between the major and pitch cylinders for internal thread.

5. Which of the following is not a name of the major diameter of an external thread?
a) Outside diameter
b) Crest diameter
c) Full diameter
d) Cone diameter
Explanation: For a straight thread, Major diameter is the diameter of the major cylinder. It is also known to as the outside diameter or full diameter for external threads. Sometimes it is also called crest diameter.

6. Which of the following is not true about the axial thickness of screw thread?
a) Measured in direction perpendicular to the axis of thread
b) Measured on pitch cylinder
c) Distance between opposite faces of same thread
d) Measured at the same thread
Explanation: In a screw thread axial thickness is the distance between the opposite faces of the same thread. It is measured on the pitch cylinder and in a direction parallel to the thread axis.

7. What is the alternative name of functional diameter?
a) Cone diameter
b) Virtual diameter
c) Root diameter
d) Inside diameter
Explanation: Functional diameter is also known as virtual diameter. For an internal or external thread, this is the pitch diameter of the enveloping thread, lead and flank angles having the full depth of engagement but not at roots and crests.

8. Which of the following is not correct when minor and major diameter have errors?
a) Will cause interference between mating parts
b) Flank contact increases
c) Less root section
d) Less wall thickness
Explanation: Errors on the minor and major diameters will cause interference in the mating thread. Due to errors in minor and major diameter, the wall thickness and root section will be less, also the flank contact will be decreases and the component will be weak in strength.

9. Which of the following are main elements, error in any of these can cause rejection of thread?
a) Major diameter and minor diameter
b) Major diameter, minor diameter and effective diameter
c) Major diameter, minor diameter, effective diameter and pitch
d) Major diameter, minor diameter, effective diameter, angle of thread and pitch
Explanation: In case of plain holes and shafts, there is one dimension only which has to be considered i.e. diameter. Errors in diameter if exceed the permissible tolerance, will result in rejection of part. But in case of screw threads there are minimum 5 important elements which are Major diameter, minor diameter, effective diameter, angle of thread and pitch and error in any one of these will result rejection of the thread.

10. What is the nature of the graph between cumulative pitch error and length of thread in case of progressive pitch error?
a) Straight line
b) Parabolic
c) Hyperbolic
d) Exponential
Explanation: Progressive pitch error can be caused due to pitch error in any generating machine or in the lead screw of a lathe. The graph between cumulative pitch error and thread length in progressive pitch error is a straight line.

11. Which of the following is the correct option for given statements about the effect of pitch error?
Statement 1: Pitch error can cause progressive tightening on assembly.
Statement 2: Tool work velocity ratio will play an important role to prevent pitch errors.
a) T, F
b) F, F
c) F, T
d) T, T
Explanation: The threads are commonly generated by a point cutting tool. For pitch to be correct, the ratio of the tool linear velocity and work’s angular velocity must be correct and constant, otherwise pitch errors will occur.

12. Which of the following is not related to the drunken thread?
a) Periodic pitch error
b) Erratic pitch error
c) Progressive pitch error
d) Irregular pitch error
Explanation: Drunken thread has erratic pitch, in which the advance of the helix is irregular in thread’s 1 complete revolution. Thread drunkenness is a case of a periodic pitch error recurring at regular intervals of 1 pitch.

13. Which of the following is the correct mathematical formula for module?
a) D/N
b) D/2N
c) 2D/N
d) 4D/N
Explanation: Module is defined as the length of the pitch circle diameter / tooth. Thus, if Pitch Circle Diameter of gear is D and number of teeth is N, then module (m) is equal to D/N. It is generally expressed in millimeter.

14. What is the standard value of clearance? (Where, m is module)
a) 0.572 x m
b) 0.182 x m
c) 0.157 x m
d) 0.821 x m
Explanation: Term clearance used in terminology of gear tooth is the radial distance from the tooth top to the bottom of a mating tooth space when the teeth are engaged symmetrically. Standard value of clearance is 0.157 m where m is module.

15. What is the value of addendum?
a) 1 module
b) 2 modules
c) 3 modules
d) 4 modules
Explanation: This is the radial distance from the pitch circle to the tooth tip. Its value is equal to 1 module. Another term diametral pitch is defined as a number of teeth per inch of pitch circle diameter.

16. What is dedendum?
a) Addendum + 2 x clearance
b) Addendum + clearance / 2
c) 2 x Addendum + clearance
Explanation: Dedendum is the radial distance from the pitch circle to the bottom of the tooth space. Dedendum is equal to Addendum plus Clearance = m + 0.157 m = 1.153 m as one addendum is a module and standard value of clearance is 0.157 m.

17. What is the flank of tooth?
a) Part of the surface of tooth which is above the pitch surface
b) Part of the surface of tooth which is below the pitch surface
c) Part of the surface of tooth which is in the middle of top and bottom of the pitch surface
d) Part of the surface of tooth which is at the top of the pitch surface
Explanation: Face of the tooth is that part of the tooth surface which is lying above the pitch surface. Flank of Tooth is that part of the tooth surface which is below the pitch surface.

18. What is tooth thickness?
a) Circular pitch / 2
b) Circular pitch / 4
c) 2x Circular pitch
d) 4 x Circular pitch
Explanation: Thickness of tooth is the distance of arc measured along the pitch circle from its intercept with one flank to its intercept with the other flank of the same tooth.
Tooth thickness = C.P./2 or πm/2.

19. What is the name of angle which is present between line of action and common tangent to the pitch circles?
a) Helix angle
c) Pitch angle
d) Pressure angle
Explanation: The angle between the line of action and the common tangent to the pitch circles is called as pressure angle. The standard values of pressure angle are 14.5 degree and 20 degree. Pressure angle is generally represented by φ.

20. What is the effect of improper alignment of each tooth?
a) Tooth thickness increases
b) Face width decreases
c) Load will not distributed evenly
d) Pitch of teeth reduced
Explanation: Good alignment of each tooth on a gear is essential, as otherwise the load will not be distributed evenly over its face. It is quite probable that the load may be carried by one edge only introducing high bearing stresses, if teeth of a gear are machined poorly.

21. Which of the following is not true about concentricity of teeth?
a) Fluctuating velocity will be noticed when not concentric
b) Can be checked by using projector
c) Inaccuracy of parts when not concentric
d) Should be tested to ensure the proper heat treatment
Explanation: Concentricity of teeth is an important item and should be checked to ensure that the set up and equipment is in good order. When teeth are not concentric then fluctuating velocity will be noticed on the pitch line while transmitting motion.

22. Which of the following option is true about an analytical method of inspection of gears?
a) Analytical method is widely used for industries
b) This method is fast
c) All individual elements of gear teeth are checked
d) More accurate
Explanation: Analytical method is slow and tedious and not of much use for industry. By analytical inspection of gears we mean that all the individual elements of the gear teeth are checked. The discrete error values of pitch, tooth profile etc can’t give a true overall assessment of the accuracy of a gear.

23. Which of the following element is not determined by analytical inspection?
a) Profile
b) Composite vibrations
c) Spacing
d) Pitch
Explanation: The analytical inspection of the gears consists in determination of these Profile, Spacing, Pitch, Backlash, Runout or eccentricity or concentricity, thickness of tooth and Lead. These teeth elements in which the errors are caused due to manufacturing errors are determined by analytical inspection.

24. Which of the following option is correct for given statements about gear measurement?
Statement 1: Improper alignment of each teeth will cause high bearing stresses.
Statement 2: Gear blank should be tested for dimensional accuracy.
a) T, F
b) F, F
c) F, T
d) T, T
Explanation: The gear blank should be tested for dimensional accuracy and eccentricity as outside diameter forms the datum from where the tooth thickness is measured, it forms an important item to be controlled. It is quite probable that the load may be carried by one edge only introducing high bearing stresses, if teeth of a gear be machined poorly.

25. Which of the following is not determined by the functional type of inspection?
b) Noise level
c) Variation in action
d) Vibration
Explanation: The functional inspection consists of carrying out the running test of gear with another gear which is more accurate and is known as master gear or control gear, to determine composite vibration, noise level, or variation in action.

26. Which of the following statement is true about inspection of gear?
a) Profile is determined by functional inspection
b) Backlash is determined by analytic inspection
c) Analytic test require running test of gear
d) Thickness of tooth is measured by functional inspection
Explanation: Functional type of inspection is done by running test of gear with another gear. It is used to determine noise level and composite variation. Analytical method is used to determine backlash, lead and runout.

#### Module 4

1. What does QA and QC stand for?
a) Quality Assurance and Queuing Control
b) Quality Adjustment and Quality completion
c) Quality Assurance and Quality control
d) Quality Adjustment and Queuing control
Explanation: QA stands for Quality Adjustment. QA is concerned with the functions related
to the attainment of the required quality. QC stands for Quality control. QC is sustaining the
product quality practically and ensuring that it meets the requirements given.

2. What is QA?
a) It is the measurement of degree to which a product satisfies the need
b) Any systematic process used to ensure quality in the process
c) Process of identifying defects
d) It is a corrective tool
Explanation: QA is a systematic process which ensures the quality of the product and
guarantees to the user that product will be safer and more reliable.

3. Which of the following option is correct regarding QA and QC?
a) QC is an integral part of QA
b) QA is an integral part of QC
c) QA and QC are independent to each other
d) QC may or may not depend on QA
Explanation: QC is based on the measurements as it concerned with practical means.
Metrology is an important tool of quality assurance.

4. Which of the following option involves material and component control?
a) Development of standards
b) Development of specification
c) Quality control
d) Feedback
Explanation: Quality and measurement control involves component control. Specification and
servicing involves feedback.

5. Arrange the steps of QA in ascending order?
a) Customer needs, material control, design development, process control, marketing
b) Material control, process control, customer need, design development, finished product
c) Customer needs, design development, material control, process control, finished product
d) Material control, servicing, process control, material control, design development
Explanation: Scheme of QA starts with customer need. They have to be converted into the
development of a specification, followed by quality and measurement control, material
control and convert into the finished product.

6. What is the first step of QA?
a) Development of standards
b) Identification of customer need
c) Servicing
d) Material control
Explanation: Identification of customer need is the first step of QA after which further basic
elements of QA are identified. QA depends not only on QC but also on the activities of the
entire company.

7. Match the following:
A) Quality assurance – 1) Process oriented
B) Quality control – 2) National physical
laboratory
C) Quality management – 3) Product oriented
D) National measurement system – 4) Overall programmer of QA
a) A-3, B-4, C-2, D-1
b) A-2, B-3, C-1, D-4
c) A-1, B-3, C-4, D-2
d) A-4, B-1, C-3, D-2
Explanation: A quantitative management is a management representative, responsible for
resolving all matters pertaining to quality and independent of other functions.

8. Which of the following is an example of QA?
a) Verification
b) Software testing
c) Validation
d) Documentation
Explanation: Software testing and validation are the examples of QC. Validation is an
example of QA. QC is a system for coordinating the efforts of groups in an organization to
improve quality.

9. Which of the following option is not correct regarding QA and QC?
a) Process capabilities should be monitored on intermittent basis
b) Measuring equipment’s must have a calibration certificate
c) Normally many inspections are done during the process of manufacturing
d) QA depends on the activities of the entire company
Explanation: Process capabilities are controlled on a continuous basis. These are used to
eliminate and detect potential causes of non-conformance.

10. Where the nodal point for National Measurement System is located?
a) Bangalore
b) Patna
c) Bombay
d) New Delhi
Explanation: Nodal point for national measurement system is NPL and located in New Delhi.
It has responsibilities like the development and management of national standards, evaluation
of measuring techniques etc.

#### Module 5

1. Quality is ______ variability.
a) opposite of
b) proportional to
c) reciprocal of
d) synonym of
Explanation: Quality is defined as the fitness of a product for use. In normal circumstances, the fitness of a product for use increases with a reduction in variability. So, Quality is reciprocal of Variability.

2. Which one of these is a dimension of quality?
a) Performance
b) Hazard rate
c) Process Capability
d) Control limits
Explanation: Performance is a key component of quality. Hence, it is counted in the dimensions of quality by Garvin (1987).

3. Performance of a product is _____
a) how long the product lasts
b) how easy it is to repair the product
c) how often the product fails
d) whether the product is capable of doing the intended job
Explanation: Performance of a manufactured product is defined as the capability of a product to do the job, for which it is designed.

4. Which one of these is not a component of quality?
a) Reliability
b) Durability
c) Acceptance sampling
d) Serviceability
Explanation: There are 8 components of quality which include reliability, durability, and serviceability. Acceptance sampling is not one of them.

5. How is the aesthetics of a product defined as?
a) How good the product performs its job
b) How good it looks
c) How fast the job of the product is completed
d) Whether the product is made exactly as the designer intended
Explanation: The visual appeal of the product is regarded as the aesthetics of the product. The looking of a product is the aesthetic dimension of quality.

6. What does reduced variability result in?
a) Increased failure rate
b) Decreased reliability
c) Fewer repair claims
d) Increased repair costs
Explanation: Reduction in variability removes harmful differences between product units. This means fewer failures, hence lesser repair claims.

7. Quality of a product is at its lowest when ____ quality component is neglected while it’s manufacturing.
a) performance
b) reliability
c) aesthetics
d) serviceability
Explanation: If a product does not carry out its job efficiently (performance), it will be of no use. So performance is a key factor of quality of any product.

8. Quality characteristics are classified into variables and ________
a) constants
b) attributes
c) standards
d) specifications
Explanation: Quality characteristics are broadly divided into two parts. Variables and Attributes are the two parts of Quality characteristics.

9. Read the following sentences and choose the correct option.
(i) Variables can only take discrete values while Attributes can take continuous values.
(ii) Variables can only take continuous values while Attributes take discrete value.
(iii) Attributes and variables are dependent on each other.
(iv) Width of an impeller blade is a variable but no. of defective blades in a lot is an attribute.
a) (i) and (iii) are correct
b) (i)and (iii) are incorrect
c) Only (i) is correct
d) (i), (ii), (iii) and (iv)
Explanation: Variable can only take continuous values. Attributes can only take discrete values. Plus, variables are independent of attributes.

10. Which one of these is physical CTQ characteristic?
a) Length
b) Appearance
c) Reliability
d) Color
Explanation: Length is a physical CTQ characteristic, whereas appearance and color are sensory CTQ characteristics. Reliability is a Time-Orientation CTQ characteristic.

11. In the low level of maturity of any organization, the technique of quality improvement that is used the most is _________
a) acceptance sampling
b) statistical process control
c) design of experiments
d) regression analysis
Explanation: In early stage of any organization, the quality knowledge to management is negligible. So acceptance sampling is chosen to get the highest level of it.

12. In the Factorial design type of design of experiments, which of these points are used?
a) Controlling noise factors
b) Outgoing inspection
c) Incoming inspection
d) Testing outputs of all possible combination of factor levels
Explanation: We cannot control noise factors. In factorial design, factors are varied together, in such a way that all possible combination of factor levels is tested.

13. Factorial design is a _______
a) off-line quality control tool
b) on-Line quality control tool
c) in-process procedure
d) redundancy plan
Explanation: Off-line quality control means, quality control before process starts. Factorial design is implemented before process starting, so it is an off-line quality control tool.

14. Control chart is a useful ______
a) manufacturing process
b) process monitoring technique
c) off-line quality control tool
d) part of acceptance sampling techniques
Explanation: Control chart is a very useful part of process monitoring tool, as it can only give information if the process is going out of control.

15. Which of these is not a part of feedback control?
a) Engineering control
b) Automatic control
c) Acceptance sampling
Explanation: The process variables are adjusted as needed, to get the output process characteristics on target value. This routine adjustment is called Engineering control or feedback control.

16. The highest reduction in the variability from one unit of product to other can be obtained by ______
a) statistical process control
b) acceptance Sampling
c) design of Experiments
d) design of Experiments with automatic control
Explanation: Design of experiments gives the highest reduction in variability. When it is combined with automatic components, the variability reduces even more.

17. Quality assurance is related to _____
a) strategic activities to ensure the financial plans
b) set of activities that ensures that the services and product meet the requirements
c) set of activities that ensures that the supplier-customer quality issues are properly resolved
d) set of activities that include inspection and planning
Explanation: Quality assurance is the set of activities, that ensure the quality levels of products and services are properly maintained, and the supplier-customer relations are good.

18. The average value of the quality characteristic corresponding to in-control state is represented by _____ in the control charts.
a) CL
b) UCL
c) LCL
d) Sample number
Explanation: The control chart contains a centre line (CL) that represents the average value of the quality characteristic corresponding to in-control state. This may be the desired value of that quality characteristic.

19. The highest value that a quality characteristic can take before the process becomes out-of-control, is called ______
a) Center line
b) Upper control limit
c) Lower control limit
d) Control limit
Explanation: The UCL is the highest value of a quality characteristic at which the process is in-control, i.e. it produces products of desired specifications.

20. The horizontal line in the control chart which shows the minimum value of a quality characteristic, before the process gets out-of-control, is called the _____
a) Upper control limit line
b) Lower control limit line
c) Desired value
d) Center line
Explanation: The lowest value for a Critical-to-quality characteristic corresponding to in-control state is shown on the control chart with the lowest horizontal line, which is called the lower control limit line.

21. In the horizontal axis of a control chart displays _______
a) Sample number
b) Time
c) Either sample number or time
d) Neither sample number or time
Explanation: The horizontal axis of a control chart displays either sample numbers or time elapsed from a certain time or from the time of process starting.

23. If for a process, 18 out of 20 points are plotted above the CL but below the upper control limit, and only 2 of 20 are plotted between the center line and the lower control limit, what can we say about the process state?
a) In-control
b) Out-of-control
c) Data is not enough to predict
d) Process state is not dependent over this data
Explanation: The above question concludes a systematic pattern. For a process to be perfectly in-control state, the plotted points on the corresponding control chart should have an essentially random pattern.

24. Shifting of mean from the current value to a new value and remaining there, is called _____ shift of the mean.
a) Continuous
b) Abrupt
c) Random
d) Sustained
Explanation: Due to some reason, it may be possible that the process mean shifts from one point to another, and remain there for quite some time. This shifting of mean is called the sustained shift of the mean.

25. A process is said to be in the statistical control if it operates with ______ of variation.
a) Chance causes
b) Assignable causes
c) Both chance and assignable causes
d) Neither chance nor assignable causes
Explanation: Chance causes of variation produce the natural variability of the stable process. As this natural variability cannot be avoided, so a process is said to be in statistical control if it operates only with chance causes of variation.

26. In the name of the OC curve, OC stands for ________
a) Operation Characteristic
b) Operating Characteristic
c) Operator Characteristic
d) Operated Characteristic
Explanation: The OC curve stands for Operating Characteristic curve which is used to develop an understanding of probability variation of the Type II error in the quality control.

27. The general theory of Control charts was first developed by ________
a) Walter A. Shewhart
b) Deming
c) ISO
d) ASQC
Explanation: W.A. Shewhart was the first person to develop an applicable theory for quality control for the processes used in manufacturing a product. This was known as the general theory of Control Charts.

28. Control charts are the part of _______ step of DMAIC process.
a) Define
b) Measure
c) Act
d) Control
Explanation: The control charts use the data from the measure step to analyze the process situation and then apply the steps to control the quality of the process. So they are used in the control step, analyze step of DMAIC process.

29. The size of sample is 5 for a process. If the process standard deviation is 0.15 micron, and the mean of process is 1.5 micron, the standard deviation of the sample average will be _______
a) 0.0500
b) 0.1000
c) 0.6710
d) 0.0671
Explanation: The standard deviation of the sample average is calculated by,
σx=σ/√n
Putting σ=0.15, n=5, we get, σx=0.0671.

30. For a process, sample size=5, process standard deviation=0.15, mean=1.5, and the std. deviation of mean is 0.0671. What will be the value of 3σ upper control limit for the construction of control chart?
a) 1.70
b) 1.29
c) 1.92
d) 0.170
Explanation: As we know, UCL3σ=;n=5; σ=0.15, x¯¯¯ = 1.5; σx=0.0671{from question}
So, UCL3σ=1.5+3(0.0671)=1.7013.

31. Quantities that can be numerically measured, can be plotted on a _________ control chart.
a) X bar
b) P chart
c) C chart
d) np chart
Explanation: A quantity that is measured on a continuous scale, i.e. it is numerically measured, can be plotted on a control chart type named, X bar control chart.

32. A single measureable quality characteristic, such as dimension, weight, or volume, is called ________
a) Variable
b) Attribute
c) Variable and an Attribute
d) Mean and variablility
Explanation: A single measurable quality characteristic is that CTQ that can be measured on a continuous scale. So it is also called a variable, be it a dimension or a weight measurement of a product unit.

33. A variable quality characteristic will have both __________
a) Mean and variability
b) Discrete and continuous values
c) Zero and infinite value
d) One or zero
Explanation: A variable quality characteristic will vary on a continuous scale. So it will have both, a mean and its variability.

34. Control of the process average or mean quality level is usually done with the ___________ control chart.
a) X bar control chart
b) S control chart
c) R chart
d) P chart
Explanation: If a quality characteristic has a mean and variability, it is called a variable. If the control of process average or mean quality level is to be done for a variable, an x bar variable control chart is used.

35. S chart is used to monitor _________ of a quality characteristic.
a) Mean
b) Range
c) Variability
d) Attributes
Explanation: S chart is a control chart used to monitor the variability of a process quality characteristic. It is variable chart as it is used for monitor variability of variables.

36. Toughness of a bolt mount on a tank is __________
a) An attribute
b) A variable
c) Variable and an attribute
d) Variability
Explanation: A quality characteristic having a numerical measurement on a continuous scale is called a variable. As the toughness of a bolt is a continuous quality characteristic, it is called a variable.

37. X chart is a ____________
a) Attribute control chart
b) Variable control chart
c) Neither a variable control chart nor an attribute control chart
d) Falls in the category of both variable and attribute control charts
Explanation: Mean is only an asset of a variable quality characteristic. As x denotes mean of a variable, x chart is counted in the variable control chart category.

38. Which of these is not an advantage of acceptance sampling over the 100% sampling plan?
a) Less expensive
b) Highly costly
c) Applicable to destructive testing
d) Lesser manpower is needed
Explanation: As lesser number of units are checked while using the acceptance sampling plan instead of the 100% sampling plan, it is less expensive, applicable to destructive testing, and needs lesser manpower.

39. Which of these is used when the test of the component is non-destructive, cheap and fast?
a) 0% inspection
b) Acceptance sampling
c) 100% sampling
d) 50% sampling
Explanation: As it will give better results in the case of 100% inspection when the test procedure of a component is non-destructive, cheap, and fast, the full lot sampling procedure is adopted.

40. Which has the lowest number of manpower required?
a) Acceptance sampling
b) 0% inspection
c) 100% inspection
d) 50% inspection
Explanation: As 0% inspection does not need any equipment or personnel to check the product component supplied by the supplier, it has the lowest number of manpower required.

41. Which has lesser probability of handling damage in between 100% inspection, and the acceptance sampling procedure?
a) 100% inspection
b) Acceptance sampling
c) Both have equal handling damage
d) Can’t be predicted
Explanation: As there is a lesser number of units used as samples in the acceptance sampling, there is less handling of the product, and hence reduced damage is there in the case of acceptance sampling.

42. Which of these quite successfully fulfills the following sentence?
“The rejection of entire lots as opposed to the simple return of defectives often provides stronger motivation to the supplier for quality improvements.”
a) 0% sampling
b) 100% sampling
c) Random % of the lot sampling
d) Acceptance sampling
Explanation: As in the case of acceptance sampling, there are only a few units selected to be returned to the supplier, instead of returning the whole lot, it motivates the supplier for quality improvements.

43. Which is the most expensive for the same testing process and product component to be tested?
a) Acceptance sampling
b) 100% sampling
c) 0% sampling
d) 50% sampling
Explanation: As the 100% sampling procedure requires the checking of whole lot, it requires more resources to be devoted towards the sampling process. This makes it the most expensive procedure of all.

44. Which generates lesser information about the products and the manufacturing process, 100% sampling or Acceptance sampling?
a) 100% sampling
b) Acceptance sampling
c) Both generate equal amount of information
d) Can’t be predicted
Explanation: As we there are lesser number of units as samples in the case of acceptance sampling rather than the 100% sampling procedure, it generates lesser information about the process and the product.

#### Module 6

1. In non-destructive testing, sound test used is a very fine and accurate method of detecting flaws in the castings.
a) True
b) False
Explanation: Sound test is a very rough test to indicate any flaws or discontinuities in the casting. The casting is suspended by suitable support and tapping is done at the surface of the casting with a hammer that makes a variation in the tone which indicates the existence of flaws. This method does not indicate the exact location and extent of the discontinuity in the casting.

2. Impact test for detection of defects in the casting is the most crude and unreliable method of non-destructive testing.
a) True
b) False
Explanation: In the impact test, the casting is subjected to a blow by the help of a hammer of known weight, which basically strikes or falls on the surface of the casting. Defective castings fail due to the impact of the blow, but this method is very crude and unreliable to the material or casting which is inspected.

3. Which of the following methods of NDT requires leak proofing of casting before inspection?
a) Impact test
b) Visual inspection
c) Sound test
d) Pressure test
Explanation: Pressure test used on castings required to be leak proof. In this method, all the openings of the casting are closed and then gas with high pressure is introduced in it. If the casting is having a porosity or another defect, then it can be detected by leaking of gas in the water when the casting is submerged into the water.

4. Which of the following types of rays is used in radiography for the inspection of castings?
a) X- rays
b) Infrared rays
c) Ultraviolet rays
d) Visible rays
Explanation: Radiography uses X-rays, these rays penetrate through the castings and makes a shadow picture on a film which is placed behind the material. These rays have a very short wave length of the order of 0.001 Angstrom. And sometimes gamma rays are also used for the inspection of castings.

5. In radiography, the penetration of rays is much easier with the less density of metal or casting.
a) True
b) False
Explanation: The ability of rays to penetrate through the metal mainly depends on the density of metal and they can penetrate more easily where less density of metal is present and it leads to the formation of shadow picture on the film. And any defects in the casting can easily be identified from the shadow picture.

6. In penetrant testing of NDT, a liquid is penetrated into the cracks of metal by the application of pressure.
a) True
b) False
Explanation: Penetrant testing method is generally used for detecting very small surface cracks and it has an advantage over the magnetic particle method that it can be used for any material. A penetrant liquid is used which is drawn into the cracks or voids by means of capillary action. In this method, there is no requirement of pressure.

7. Which of the following methods of inspection uses high frequency of sound waves for the detection of flaws in the castings?
a) Penetrant test
c) Pressure test
d) Ultrasonic inspection
Explanation: Ultrasonic inspection is used to detect defects like cracks and porosity within the interior of the casting or material. This method uses reflection and transmission of high frequency sound waves, which are much higher than the audible range and then these waves are made pass through the casting for inspection.

8. In ultrasonic inspection, a signal processing technique is used for the accurate indication of porosity in the castings.
a) True
b) False
Explanation: A signal processing technique is used for accurately verifying the presence of porosity and also to determine the size and volume fraction. This is mainly done by measuring the changes in frequency by using a broad band transducer, in which the front and the back surface signals of the casting are acquired and digitized.

9. Which of the following terms changes in the eddy current testing method for the detection of defects in the castings?
a) Resistance
b) Impedance
c) Conductivity
d) Capacitance
Explanation: In the method of eddy current testing, the impedance of a coil is changes and the coil is brought close to a conductive material which indicates the eddy current induced by the coil and thereby indicates various properties and also the defects of the casting. This method can be used effectively with both ferromagnetic and non-ferromagnetic materials.

10. There are no restrictions in the eddy current testing method; it can detect defects up to high depth in the castings.
a) True
b) False
Explanation: Eddy current inspection is generally restricted to the depth less than 6mm, that’s why it is not as sensitive to small open defects of high depth as liquid penetrant testing (LPT) or magnetic particle inspection (MPI). But it can replace LPT method for detection of surface connected discontinuities.

11. Eddy current testing method can also be used for the evaluation of heat damage to the metal alloys.
a) True
b) False
Explanation: Eddy current conductivity testing method is commonly used to assess heat damage of various heat treatable alloys. In order to have a quantitative assessment of heat damaged material, the establishment of conductivity, hardness and strength, a (CHS) relationship is required for each alloy.

12. Acoustic emission testing method is basically employed for the detection of surface discontinuities on the castings.
a) True
b) False
Explanation: Acoustic emission testing method, in which solid materials emit sound or acoustic emission when they are stressed mechanically or thermally to the point where deformation or fracturing occurs. This creates elastic waves which can be analyzed by an acoustic emission test system to monitor the condition of the material or casting under stress.

13. Equipment used for inspection of inside portion of hollow chamber or narrow tube is known as ___________
a) Endoscope
b) Telescope
c) Borescope
d) Flexiscope
Explanation: Borescope is used for visual of inside portion of the hollow chamber.

14. What is the value of average number of grains in per square inch for ASTM 11?
a) 2048
b) 1024
c) 6
d) 5
Explanation: According to ASTM standard E1112, ”standard test methods for determining average grain size”:
n = 2G-1, where ‘G’ is the grain size number and ‘n’ represents the average number of grains per square inch at a magnification of 100X.
Given ASTM grain size 12, thus, n = 211-1 = 210 = 1024.

15. Which of the following property will be more in fine grained structure?
a) Ductility
b) Corrosion resistance
c) Creep resistance
d) Hardness
Explanation: Finer the grain size (lower the grain size), more is the number of grain boundaries, thus more is the yield strength, thus more is the ductility. This is the reason why we can easily draw a fine-grained structure into wires.

16. Which of the following property will be more in coarse grain structure?
a) Ductility
b) Corrosion resistance
c) Hardness
d) Toughness
Explanation: Grain boundaries are susceptible to corrosion. Coarse grain structure has less grain boundaries, thus has greater corrosion resistance.

17. Which of the following penetrating liquid is used in a liquid penetration test?
a) Water
b) Chlorine based solvent
c) Petroleum based carrier fluid
d) Fluorine based solvent
Explanation: In liquid penetration test, either petroleum-or-water based carrier fluids are used as solvents or cleaners according to the type of penetrant used. Petroleum based carrier fluid is used as penetrating liquid in liquid penetration test along with fluorescent red colour dye for visible light.

18. Which of the following non destructive testing is used to detect change in composition of any material?
a) Liquid penetration test
b) Ultrasonic test
c) Eddy current test
Explanation: Radiography enables us to detect the change in composition. X-rays or γ-rays are used in radiography technique.

19. Which of the following compound is used for fine polishing?
a) Aluminum oxide
b) Nitric oxide
c) Silicon carbide
d) Iron oxide
Explanation: Powder form of aluminum oxide is used for fine polishing process. It is surface treatment process.

20. Etching of specimen is done to achieve ___________
a) Visible grain boundary
b) Invisible grain boundary
c) Toughness
d) Hardness
Explanation: Etching is done to obtain visible grain boundary. It is a surface treatment process.

21. In which type of test the capillary action principle is used?
a. Probe test
b. Bend liquid test
c. Dye penetrant test
d. None of the above

22. Non-destructive testing is used to determine
a. location of defects
b. chemical composition
c. corrosion of metal
d. All of these

23. Which among the following is not a type of Non-destructive testing?
a. compression test
b. visual testing
c. ultrasonic testing
d. eddy current testing

24. Identify the type of destructive testing
b. Dye penetrant test
c. Creep test
d. All of the above

25. Which among the following is the last step in magnetic particle test method?
a. observation and inspection
b. circular magnetization
c. demagnetization
d. magnetization

26. Which of the following statements is/are true for ultrasonic test?
a. Equipment used for ultrasonic testing is portable
b. Complicated shapes can be easily scanned
c. Waves generated are health hazardous
d. All the above statements are true
Answer: Equipment used for ultrasonic testing is portable

27. During radiography test, which region absorbs less radiation and transmits more?
a. Low and high density regions absorb and transmit same amount of radiation
b. High density region
c. Low density region
d. None of the above

28. Which test is used to determine dimensions of any object?
a. Ultrasonic test
b. Torsion test
c. Eddy current test
d. All of these tests can be used to determine dimensions of any object

29. Eddy current test is used to detect
a. cracks
b. hardness
c. conductivity
d. All of the above