The least count of the main scale of a screw gauge is 1 mm . The minimum number of divisions on its circular scale required to measure diameter of a wire is:
- (A)50
- (B)200✓ Correct
- (C)100
- (D)500
Answer: (B)
Solution
The least count of a screw gauge is its pitch divided by the number of divisions on the circular scale, . To just resolve a diameter of the least count must be , while the pitch is . So , which gives divisions.
JEE Main · 2019 · 12 Jan 2019 · Shift 1 · Single correct option