The sensitivity of a galvanometer of resistance 406 ohm is increased by 30 times. The shunt used is
Answer & explanation
Correct answer: option 2
$ \text{Sensitivity is given by }S = \frac{\theta}{I}$
$ S_1 = \frac{\theta}{I} , S_2 = \frac{\theta}{I_g}$
$\text{It is given that }\frac{S_1}{S_2} = 30$
$ \Rightarrow \frac{I}{I_g} = 30$
$\text{The Shunt } R_s = \frac{I_g R_g}{I - I_g} = \frac{406}{29} = 14\Omega$