Q 12-04-033NEETJEE MainMedium
The number of turns in the coil of a moving-coil galvanometer is doubled, using the same wire so that its resistance also doubles. Its current sensitivity and voltage sensitivity change as follows:
Answer: (A) current sensitivity doubles; voltage sensitivity is unchanged
Current sensitivity $\dfrac{\phi}{I} = \dfrac{NAB}{k}$, so it doubles with $N$.
Voltage sensitivity $\dfrac{\phi}{V} = \dfrac{NAB}{kR}$. Both $N$ and $R$ double, so it is unchanged.
Solution by Sreeraj P, M.Sc Physics