A moving coil galvanometer has resistance
Question:

A moving coil galvanometer has resistance $50 \Omega$ and it indicates full deflection at $4 \mathrm{~mA}$ current. A voltmeter is made using this galvanometer and a $5 \mathrm{k} \Omega$ resistance. The maximum voltage, that can be measured using this voltmeter, will be close to:

1. (1) $40 \mathrm{~V}$

2. (2) $15 \mathrm{~V}$

3. (3) $20 \mathrm{~V}$

4. (4) $10 \mathrm{~V}$

Correct Option: , 3

Solution:

(3) $V=i_{g}(G+R)=4 \times 10^{-3}$

$(50+5000)=20 \mathrm{~V}$