# To Measure Diameter of a Small Spherical/Cylindrical Body Using Vernier Callipers - Physics Practical Class 11 Viva Questions with Answers

1. Define vernier callipers.
2. Answer. It is a measuring device mainly used for measuring linear dimensions. Vernier callipers are used for measuring the diameters of round objects.

3. What does a calliper mean.
4. Answer. Calliper is a device used to measure the dimensions of an object.

5. What are the scales in a Vernier Calliper.
6. Answer. Scales on a Vernier callipers are The main scale and a Vernier scale.

7. What is the least count of vernier calliper also known as?
8. Answer. The least count of vernier calliper is also known as the vernier constant.

9. Define the vernier constant or least count.
10. Answer. It is the difference between the value of one main scale division (MSD) and one vernier scale division (VSD).

11. What are the various sources of errors while measuring in vernier callipers?
12. Answer. Sources of error are

1. When jaws are not at the right angle to the main scale.
2. Parallax while noting the observations.
3. Dull graduations on both scales.
4. Loose fixing of the vernier scale on the main scale.
13. What is the smallest distance measured along the vernier callipers known as?
14. Answer. It is known as the least count.

15. Who invented the vernier scale?
16. Answer. The Vernier scale was invented by Pierre Vernier, the French mathematician.

17. What is the formula to find the difference between one Main Scale Division (MSD) and one Vernier Scale Division (VSD)?
18. Answer. It is given by the formula: n(VSD)=(n-1)MSD.

If 1 MSD = 1 mm and 1 VSD = 0.9 mm. What is the value of least count?

Answer. Least count = (MSD – VSD) = 1-0.9mm = 0.1mm

19. List the two sectors which use vernier callipers?
20. Answer. The vernier callipers are used in the aerospace field and the steel manufacturing sector.

21. State true or false: Each division of the Vernier scale is bigger than each main scale division.
22. Answer. FALSE. Each division of the Vernier scale is smaller than every division of the main scale.

23. At which angle should an observer note the readings in vernier callipers?
24. Answer. Observations should be taken at right angles (90 degrees).

25. What is meant by inside callipers?
26. Answer. Inside callipers are the device used to measure the internal size of an object.

27. The external size of an object is measured using which type of callipers?
28. Answer: The external size of an object is measured using the outside calliper.

29. Calculate the least count when n divisions on the VSD coincide with (n-1) division on the MSD.
30. Answer. It is given by the formula: LC =

$$\begin{array}{l}(1-\frac{n-1}{n})\end{array}$$
MSD

31. Define zero error.
32. Answer. It is defined as the condition where the measuring device registers a reading when there should not be any reading.

33. What is the formula to calculate the actual reading?

Actual reading = Main scale + Vernier scale – (Zero error)

35. What are the types of zero error?
36. Answer. Types of zero error are Positive zero error and Negative zero error.

37. What is the main function of the thumbscrew?
38. Answer. The thumbscrew is used to provide a grip to the users so that sliding of the jaws becomes effortless. Thumbscrew is found at the bottom of the vernier scale.

39. List the types of vernier callipers.

41. What is the main function of the vernier scale?
42. Answer. It is mainly used to offer accuracy to the main scale reading by dividing the reading into smaller increments.

43. What is the value of the lowest main scale division?
44. Answer. The value of the lowest main scale division is 1 mm.

45. The main scale is movable or stationary?
46. Answer. The main scale is stationary.

47. Which is the larger scale in a vernier calliper?
48. Answer. The main scale is the larger scale in the vernier calliper.

49. Which jaw is used to measure the internal diameter of an object?
50. Answer. Inside small jaws are used for measuring the internal diameter of an object.

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