Q162 / 180 · KCET 2011 · Physics
The deflection in a moving coil galvanometer is reduced to half when it is shunted with a $40 \Omega$ coil. The resistance of the galvanometer is
- A$80 \Omega$
- Correct answerB$40 \Omega$
- C$20 \Omega$
- D$15 \Omega$
Solution
We know,
$$
\begin{gathered}
\frac{I_{G}}{I}=\frac{1}{2} \\
\frac{S}{G+S}=\frac{1}{2} \\
\frac{I_{G}}{I}=\frac{40}{G+40}=\frac{1}{2} \\
G=40 \Omega
\end{gathered}
$$
Hence, the correct answer is option: 'B'.