JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Units & Measurement

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If the screw on a screw-gauge is given six rotations, it moves by 3 mm on the main scale.
If there are 50 divisions on the circular scale the least count of the screw gauge is
  1. (A)0.001 cm✓ Correct
  2. (B)0.001 mm
  3. (C)0.01 cm
  4. (D)0.02 mm

Answer: (A)

Solution

The screw advances mm in six turns, so its pitch is mm per turn. With divisions on the circular scale, the least count is mm, which is cm.

JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Single correct option

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