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JEE Main 2026 (28 Jan, Shift 2) · Least Count, Vernier Callipers & Screw Gauge

Least Count, Vernier Callipers & Screw Gauge question from JEE Main 2026 (28 Jan, Shift 2)

Q4JEE Main 2026 · 28 JAN · SHIFT 2Medium

Least Count, Vernier Callipers & Screw Gauge

In an experiment, a set of readings are obtained as follows: 1.24 mm, 1.25 mm, 1.23 mm, 1.21 mm. The expected least count of the instrument used in recording these readings is _______ mm.

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Answer: (a)

  1. The last significant digit of each reading is in the 0.01 mm place.
  2. Readings differ in steps of 0.01 mm, so the instrument reads to 0.01 mm.
  3. So the least count is (a) 0.010.01 mm.
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