Question

How is galvanometer converted into a voltmeter?

(a) By connecting a high resistance multiplier in parallel to the galvanometer

(b) By connecting a low resistance multiplier in parallel to the galvanometer

(c) By connecting a low resistance multiplier in series with the galvanometer

(d) By connecting a high resistance multiplier in series with the galvanometer

The question was posed to me in an international level competition.

My doubt is from Moving Coil Galvanometer topic in division Moving Charges and Magnetism of Physics – Class 12

Answer 1

The correct choice is (d) By connecting a high resistance multiplier in series with the galvanometer

For explanation I would say: A galvanometer can be converted into voltmeter of given range by connecting a high resistance called multiplier in series with the galvanometer, whose value is given as:

R = \((\frac {V}{I_g})\) – G

Where V is the voltage to be measured, Ig is the current for full scale deflection of galvanometer and G is the resistance of galvanometer.