The given circuit shows a uniform straight wire $A B$ of 40 cm length fixed at both ends. In order t

Question

The given circuit shows a uniform straight wire $A B$ of 40 cm length fixed at both ends. In order to get zero reading in the galvanometer $G$, the free end of $J$ is to be placed from $B$ at

Professor PC Thomas Classes · Answer

(d) : The galvanometer shows zero reading when no current passes through it. Condition of balanced metre brige, $\frac{R_1}{R_2}=\frac{x}{(l-x)}$ Given : $l=40 \mathrm{~cm}, R_1=8 \mathrm{~cm}$ and $R_2=12 \mathrm{~cm}$ \ $ \begin{aligned} & \frac{8}{12}=\frac{x}{40-x} \ & 	ext { or } \quad 320-8 x=12 x \ & 	herefore \quad x=16 \mathrm{~cm} \end{aligned} $ From $B, 40-16=24 \mathrm{~cm}$