Q 12-04-127JEE MainJEE Main 2023 (13 Apr, Shift 1)Medium
When a resistance of $5\ \Omega$ is shunted with a moving coil galvanometer, it shows a full scale deflection for a current of $250\ \text{mA}$, however when $1050\ \Omega$ resistance is connected with it in series, it gives full scale deflection for $25$ volt. The resistance of galvanometer is ______ $\Omega$.
Numerical value type. Enter your answer.
Answer: 50
Series: $I_g(G+1050)=25$. Shunt: $I_gG=(0.25-I_g)\times5$.
Substituting $I_g=\dfrac{25}{G+1050}$: $25G=1.25(G+1050)-125\Rightarrow23.75G=1187.5\Rightarrow G=50\ \Omega$.
Solution by Sreeraj P, M.Sc Physics