Question

Sensitivity of moving coil galvanometer is '$s$'. If a shunt of ${\left(\frac{1}{8}\right)}^{th}$ of the resistance of galvanometer is connected to moving coil galvanometer, its sensitivity becomes:

• A. $\frac{s}{3}$
• B. $\frac{s}{6}$
• C. $\frac{s}{9}$
• D. $\frac{s}{12}$

Answer 1

Answer: (C)

$\frac{s}{9}$

$S=\frac{G}{8}$ $S=\frac{G}{n-1}$

Now $\frac{G}{8}=\frac{G}{n-1}$

$\Rightarrow n=9$

Since range of a galvanometer is increased nine times its sensitivity reduces to $\frac{1}{9}$

$\therefore S^{\prime }=\frac{s}{9}$