Physics - Error Question with Solution | TestHub

Case $1$: No shunt is added

The initial balancing length $l$ of the bridge is,

$\frac{2}{3}=\frac{l}{100-l}$

$$\begin{gathered} \Rightarrow 200-2l=3l \\ \Rightarrow l=40 \mathrm{cm} \end{gathered}$$

Case $2$: When shunt is added

The new balancing length is, $l_1=22.5+40=62.5 \mathrm{cm}$

So, $\frac{62.5}{37.5}=\frac{2}{\left({\displaystyle \frac{3X}{3+X}}\right)}$

$\Rightarrow X=2$.