Solved Examples Evample 18. A bar measured with a vernier caliper is found to be 180mm long. The temperature during the measurement is 10°C. The measurement error will be if the scale of the vernier caliper has been graduated at a temperature of 20°C : (a = 1.1 x 10-5 °C 1. Assume that the length of the bar does not change.) (A) 1.98 x 10-1 mm (B*) 1.98 x 10-2 mm (C) 1.98 x 10-3 mm (D) 1.98 x 10-4 mm Solution : True measurement = scale reading [1 + a (0 - 0)] = 180 x {1+ (10 - 20) (-1.1 x 10-5)} measurement error = true measurement - scale reading = 180 x {1+ (10-20) « (-1.1 x 10-5)}- 180 = 1.98 x 10-2 mm