Q 12-04-211JEE MainJEE Main 2019 (9 Apr, Shift 1)Easy
A moving coil galvanometer has resistance $50\ \Omega$ and it indicates full deflection at $4\ \text{mA}$ current. A voltmeter is made using this galvanometer and a $5\ \text{k}\Omega$ resistance. The maximum voltage, that can be measured using this voltmeter, will be close to
Answer: (C) $20\ \text{V}$
The series resistance is added to the galvanometer:
$$V = I_g(G + R) = 4\times10^{-3}\times(50 + 5000) = 20.2\ \text{V} \approx 20\ \text{V}$$
Solution by Sreeraj P, M.Sc Physics