A galvanometer of resistance 20 Ω is shunted by a 2 Ω resistor. What part of the main current flows through the galvanometer ?

Q: A galvanometer of resistance 20 Ω is shunted by a 2 Ω resistor. What part of the main current flows through the galvanometer ?

Sol: Ig G = Is S

Ig G = ( I – Ig ) S

Ig ( G + S ) = I S

Given G = 20 Ω ; S = 2 Ω

$\large \frac{I_g}{I} = \frac{S}{G + S} = \frac{2}{20 + 2} $

$\large \frac{I_g}{I} = \frac{1}{11} $

Hence , (1/ 11)th part of current is passing through galvanometer.