JEE Main · 2023 · 30 Jan 2023 · Shift 1 · Units & Measurement

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In a screw gauge, there are 100 divisions on the circular scale and the main scale moves by 0.5 mm on a complete rotation of the circular scale. The zero of circular scale lies 6 divisions below the line of graduation when two studs are brought in contact with each other. When a wire is placed between the studs, 4 linear scale divisions are clearly visible while

4 6^{th}

division the circular scale coincide with the reference line. The diameter of the wire is

____

\times 1 0^{- 2} mm

Answer: 220

Solution

The least count is

\frac{0.5 mm}{100} = 5 \times 1 0^{- 3} mm

. With the circular-scale zero resting

6

divisions below the reference line the gauge has a positive zero error of

6 \times 5 \times 1 0^{- 3} = 0.03 mm

. The wire reading is

MSR + CSR - zero error = 4 \times 0.5 + 46 \times 5 \times 1 0^{- 3} - 0.03 = 2 + 0.23 - 0.03 = 2.2 mm

. Expressed in the required units this diameter is

220 \times 1 0^{- 2} mm

, so the value is

220

JEE Main · 2023 · 30 Jan 2023 · Shift 1 · Integer answer

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JEE Main · 2023 · 30 Jan 2023 · Shift 1 · Units & Measurement

Solution

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