Question

The potentiometer wire $AB$ is $600cm$ long . At what distance from the point $A$ should the jockey touch the wire to get zero deflection in the galvanometer ?

Answer 1

we have,

$\frac{E}{2}=(15-x)r{I}_1\Rightarrow E=2(15-x)r{I}_1$

$E=(15-x)r{I}_1+(1+x)r{I}_1=16r{I}_1$

$2(15-x)16$

$x=7$

let the jockey be placed at a distance of y cm from the left

$\frac{y}{600-y}=\frac{15-x}{x}=\frac{8}{7}$

$\Rightarrow 7y=4800-8y$

$y=\frac{4800}{15}=320cm$