Question

When 0.010A current flows through a moving coil galvanometer, it gives full deflection. Then, it is converted into a voltmeter which gives a reading of 10 V using an external resistance of 950 Ω. What is the resistance of the galvanometer (G)?

(a) 40 Ω

(b) 50 Ω

(c) 60 Ω

(d) 70 Ω

I got this question in an internship interview.

I want to ask this question from Moving Coil Galvanometer topic in division Moving Charges and Magnetism of Physics – Class 12

Answer 1

The correct choice is (b) 50 Ω

Easy explanation: Given: V = 10 V; Ig = 0.010A; R = 950 Ω

Required equation ➔ R = \((\frac {V}{I_g})\) – G ➔ G = \((\frac {V}{I_g})\) – R

G = \((\frac {10}{0.010})\) – 950

G = 1000 – 950

G = 50 Ω

Therefore, the resistance of galvanometer is 50 Ω.