Question

The deflection in a galvanometer falls from $50$ division to $20$ devisions, when a $12\Omega$ shunt is applied. The galvanometer resistance is

• A. $18\Omega$
  
• B. $24\Omega$
• C. $30\Omega$
• D. $36\Omega$

Answer 1

Answer: (A)

$18\Omega$

$I=50k;$

$I_g=20k$, where $k$ is the figure of merit of galvanometer;

$S=I_g{R}_g(I-I_g);$

So $12=\frac{20k.R_g}{(50k-20k)}$

On solving we get

$R_g=18ohms.$