# To Measure Diameter of a Given Wire Using Screw Gauge - Class 11 Physics Practical Viva Questions with Answers

1. What is a screw gauge?
2. Answer. It is an instrument used to calculate the thickness of a metal plate or diameter of a wire and to mainly calculate the dimensions of small objects, up to 0.001 mm more precisely.

3. Can the screw gauge measure spherical or cylindrical objects?
4. Answer. Yes, the screw gauge can measure spherical or cylindrical objects.

5. Define the pitch of the screw gauge.
6. Answer. It is the distance moved by the screw when the screw completes one rotation between the consecutive threads.

7. What would be the least count if a screw gauge has a 1 mm pitch and 100 divisions on the circular scale?
8. Answer. The least count is given by the formula:

Least count = 1mm/100 = 0.01mm

9. To avoid a back-lash error in the screw, in which direction the screw has to be moved?
10. Answer. A screw has to be moved in the same direction to avoid the back-lash error.

11. What is the use of a lock knob?
12. Answer. The lock knob is placed near the spindle and is used to lock the movement of the spindle.

13. Name the stationary sections of a screw gauge.
14. Answer. Stationary sections of a screw gauge are Spindle, Thimble Lock, Anvil, Frame, Sleeve, Thimble, and Ratchet Stop.

15. The object to be measured is placed between which sections of a screw gauge?
16. Answer. The object to be measured is placed between the anvil and the spindle.

17. To tighten the object, in which direction the ratchet counter is rotated?
18. Answer. The ratchet counter is rotated in the clockwise direction to tighten the object.

19. What is the formula to calculate the pitch of the screw gauge?
20. Answer. The pitch of the screw gauge is given by the formula

Pitch = (distance moved by a screw)/(no. of rotations given)

21. What is a micrometre screw gauge?
22. Answer. It is an instrument used for calculating the thickness of small sheets such as glass or plastics and the diameter of thin wires.

23. What is the formula to calculate the least count of the micrometre screw gauge?
24. Answer. Least count of micrometre = pitch of the screw gauge / total number of divisions on a circular scale.

25. Who invented the first screw gauge?
26. Answer. The first screw gauge was created in the 17th century by William Gascoigne.

27. Can we get the back-lash error in the screw gauge?
28. Answer. Yes, a back-lash error can be seen while measuring in the screw gauge.

29. What are the various sources of error while performing the screw gauge experiment?
30. Answer. Various sources of error while performing the screw gauge experiment are friction in the screw, back-lash error and parallax, unequal division of circular scale divisions and uniformity in the wire.

31. The circular scale is engraved on which part of the screw gauge?
32. Answer. A circular scale is engraved horizontally on the thimble of the screw gauge.

33. Define pitch scale.
34. Answer. It is the scale that measures the distance travelled by a spindle per revolution. The pitch scale is marked on the barrel of the screw gauge.

35. On which principle does the screw gauge operate?
36. Answer. The screw gauge operates on the principle of a screw.

37. Name the rotating portion of the screw gauge.
38. Answer. The thimble is the rotating portion of the screw gauge.

39. When the thimble is rotated, what happens to the anvil?
40. Answer. The spindle will travel towards the anvil when the thimble is rotated.