Question

Derive the expression to find the unknown resistance in the balanced condition of wheastone bridge.

Answer 1

$P=$ Resistance of $AB=kl$

$G=$ Resistance of $BC=k(100-l)$

Applying wheatstone bridge condition

$\frac{R}{X}=\frac{P}{G}=\frac{kl}{k(100-l)}$

or $X=\frac{(100-l)}{l})R\leftarrow$Unknown resistance