A galvanometer of resistance ' $G$ ' is shunted by a resistance of $S \Omega$. To keep the main current in…
A galvanometer of resistance ' $G$ ' is shunted by a resistance of $S \Omega$. To keep the main current in the circuit unchanged, the resistance to be put in series with the same galvanometer is
$\frac{\mathrm{G}^2}{\mathrm{~S}+\mathrm{G}}$
$\frac{5 G}{S+G}$
$\frac{G}{S+G}$
$\frac{S^2}{S+G}$
Solution
Current will be unchanged if resistance remains same to
$\begin{aligned} & G=\frac{G S}{G+S}+R \\ & \Rightarrow R=G-\frac{G S}{G+S}=\frac{G^2}{G+S}\end{aligned}$