Question

The voltmeter reading up to 1000 mv is calibrated by a potentiometer. An emf of 1.08v is balanced across 5.4m length of the wire. When voltmeter reading is 0.9v the balancing length is 4.55m.The error in the voltmeter reading is

Answer 1

is given that an emf of 1.08 V is balanced across a wire of length of 5.4 meters.

The potential gradient = .

It is also given that when the voltage reading is 0.9 V, the balancing length is 4.55 meters.

Therefore, the required voltage = .

Hence, the error = 0.9 - 0.91 = -0.01