JEE Main · 2026 · 28 Jan 2026 · Shift 1 · Units & Measurement

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When both jaws of vernier callipers touch each other, zero mark of the vernier scale is right to zero mark of main scale,

4^{th}

mark on vernier scale coincides with certain mark on the main scale. While measuring the length of a cylinder, observer observes 15 divisions on main scale and

5^{th}

division of vernier scale coincides with a min scale division. Measured length of cylinder is ____ mm. (Least count of Vernier calliper

= 0.1 mm

)

(A)15.4
(B)15.1✓ Correct
(C)15.5
(D)15.9

Answer: (B)

Solution

Zero error: The 4th vernier division coincides, so zero error =

+ 4 \times 0.1 = + 0.4 mm

(positive zero error).

Reading = MSR + (VSR × LC) − Zero Error

= 15 + (5 \times 0.1) - 0.4 = 15 + 0.5 - 0.4 = 15.1 mm

JEE Main · 2026 · 28 Jan 2026 · Shift 1 · Single correct option

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