In a Vernier calipers, when the two jaws are brought into contact, the zero of the Vernier scale lies to the right of the zero of the main scale. The 7th Vernier division coincides with a main-scale mark. If one main-scale division is 1 mm and the Vernier has 10 divisions, what is the zero error of the instrument?
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Question

In a Vernier calipers, when the two jaws are brought into contact, the zero of the Vernier scale lies to the right of the zero of the main scale. The 7th Vernier division coincides with a main-scale mark. If one main-scale division is 1 mm and the Vernier has 10 divisions, what is the zero error of the instrument?

Options

G1 Physics · Accepted Answer

The zero of the Vernier scale lies to the right of the main-scale zero, so the zero error is positive. Least count: LC = 1 mm ÷ 10 = 0.1 mm. The 7th Vernier division coincides with a main-scale mark, so the zero reading is zero error = 7×LC = 7×0.1 mm = 0.7 mm. Converting to centimetres: 0.7 mm = 0.07 cm. Therefore the Vernier calipers has a positive zero error of 0.07 cm. Correct option: C.