Question

A galvanometer having a resistance of 20 Ω shows a full scale deflection with a current of 1 mA. How can it be converted into a voltmeter with a range of 0-10 V?

Answer 1

To convert a galvanometer into a voltmeter, we have to add a resistance R is series.

Here,

I_g = 1 mA = 10⁻³ A

V_AB = I_g (G + R)

⇒ 10 = 10⁻³ (20 + R)

⇒ `10/10^-3` = 20 + R

⇒ 10000 = 20 + R

⇒ R = 9980 Ω