Q53 / 54 · JEE Advanced 2022 (Paper 2) · Physics
Area of the cross-section of a wire is measured using a screw gauge. The pitch of the main scale is . The circular scale has divisions and for one full rotation of the circular scale, the main scale shifts by two divisions. The measured readings are listed below.
Measurement condition Main scale reading Circular scale reading Two arms of gauge touching each other without wire division divisions Attempt-: With wire divisions divisions Attempt-: With wire divisions divisions
What are the diameter and cross-sectional area of the wire measured using the screw gauge?
Area of the cross-section of a wire is measured using a screw gauge. The pitch of the main scale is . The circular scale has divisions and for one full rotation of the circular scale, the main scale shifts by two divisions. The measured readings are listed below.
| Measurement condition | Main scale reading | Circular scale reading |
| Two arms of gauge touching each other without wire | division | divisions |
| Attempt-: With wire | divisions | divisions |
| Attempt-: With wire | divisions | divisions |
What are the diameter and cross-sectional area of the wire measured using the screw gauge?
- A
- B
- Correct answerC
- D
Solution
Note: This question is given bonus by JEE council.
In one rotation 2 divisions of the main scale are crossed. Therefore, the least count of the screw gauge is
And the zero error is
Reading-1
Reading-2
Therefore, average reading
Average mean error
Diameter
Area
Hence, the correct answer is option: 'C'.