Question

The main scale of a verniercallipers reads in millimeter and its vernier in divided into 10 divisions which coincide with a division of the main scale. When the two jaws of the instrument touch each other the seventh division of the vernier scale coincide with a scale divisions and the zero of the vernier lies to the right of the zero of mains scale. Furthermore when a cylinder is tightly placed along its length between the two jaws, the zero of the vernier scale lies slightly to the left of 3.2 cm and the fourth vernier division coincides with a scale division. What is the length of the cylinder?

• A. (a) 3.14 cm
• A. (b) 3.07 cm
• A. (c) 3.2 cm
• A. (d) 3.04 cm

Answer 1

(b)

Sol. LC = 0.1 mm

The error = 7 × 0.1 = 0.7 mm = 0.07 cm

True reading = 3.1 + 4 (0.01) – 0.07 = 3.07 cm