Question

A cell with considerable internal resistance is connected directly across the terminals of the potentiometer wire. The potential gradient is now ‘G’. Now the potentiometer wire is replaced by another wire of same material but double the length and having the same radius as that of the original wire. The new potential gradient on the wire with the same cell connected as before is A) G/2 B) G C) G/2

Answer 1

Given : A cell with considerable internal resistance is connected directly across terminal of the potentiometer wire. The potential gradient is ‘G’. now the potentiometer wire is replaced by another wire of same material but double the length and having the same radius as that of the original wire.

To find : The new potential gradient on the wire with the same cell connected as before.

solution :

principle of potentiometer,

V = kl,

where k is potential gradient, l is length of wire and v is potential.

here it is clear that, k ∝ 1/l

so, if the length of wire is doubled, potential gradient will be halved.

i.e., new potential gradient is G/2.

Therefore option (C) G/2 , is correct choice.