A galvanometer of resistance, $G$ is shunted by a resistance $S \mathrm{~ohm}$. To keep the main current in…
A galvanometer of resistance, $G$ is shunted by a resistance $S \mathrm{~ohm}$. To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is
$\frac{S^2}{(S+G)}$
$\frac{S G}{(S+G)}$
$\frac{G^2}{(S+G)}$
$\frac{G}{(S+G)}$
Solution
Current will be unchanged if resistance remains same so
$\begin{aligned}
& G=\frac{G S}{G+S}+R \\
& R=G-\frac{G S}{G+S} \\
& R=\frac{G^2}{G+S}
\end{aligned}$
.
$\begin{aligned}
& G=\frac{G S}{G+S}+R \\
& R=G-\frac{G S}{G+S} \\
& R=\frac{G^2}{G+S}
\end{aligned}$
.