Question

A slide wire potentiometer has 10 wires of 2 m each. With the help of a standard voltage source of 1.045 V, it is standardized by keeping the jockey at 104.5 cm. If the resistance of potentiometer wires is 2000 Ω, then the value of working current is?

(a) 1 mA

(b) 10 mA

(c) 0.1 mA

(d) 0.5 mA

This question was addressed to me in exam.

Enquiry is from Advanced Problems on Measurement of Low Medium and High Resistance in chapter Measurement of Resistance of Electrical Measurements

Answer 1

The correct option is (b) 10 mA

Explanation: Total length of the slide wire = 10 × 200

Total resistance of slide wire = 2000 Ω

∴ Resistance per cm = 1 Ω

Resistance of 104.5 cm = 104.5 Ω

This corresponds to a voltage of 1.045 V

∴ Current = \(\frac{1.045}{104.5}\) = 10 mA.