The potentiometer wire AB shown in figure is 40 cm long. Where should the free end of the galvanometer be connected on AB so that the galvanometer may show zero deflection?

Question

Philoid · Accepted Answer

Concepts/Formula used:

Wheatstone bridge:

The condition for no deflection through the galvanometer is

Here, and

Let the potentiometer wire be at l cm from A when there is no deflection through galvanometer.

Let the resistance per cm of the potentiometer wire be be ρ .

Hence, and .

Using the equation when there is no deflection for a Wheatstone bridge/potentiometer, we have

Hence, the free end of the galvanometer must be 16cm from point A.