Q 12-04-093JEE MainJEE Main 2024 (9 Apr, Shift 1)Easy
A galvanometer has a coil of resistance $200\ \Omega$ with a full scale deflection at $20\ \mu\text{A}$. The value of resistance to be added to use it as an ammeter of range $(0 - 20)\ \text{mA}$ is:
Answer: (B) $0.20\ \Omega$
A shunt is connected in parallel:
$$S = \frac{I_gG}{I - I_g} = \frac{20\times10^{-6}\times200}{0.02 - 0.00002} \approx \frac{4\times10^{-3}}{0.02} = 0.20\ \Omega$$
Solution by Sreeraj P, M.Sc Physics