Question

A potentiometer wire of length 5m is connected to a battery for a certain cell having negligible resistance the null point is obtained at 250cm if length of potentiometer wire is increased by 1m where will be the new position of the null point?

Answer 1

The new null point will be obtained at 300 cm.

Explanation :

The initial length of potentiometer wire = 5 m

Final length of potentiometer wire = 5+1 = 6 m

Initial balance point = 250 cm = 2.5 m

we know that in a potentiometer the balance point is directly proportional to the length of the wire,

=> N/2.5 = 6/5

=> N = 6/5 x 2.5 = 3 m = 300 cm

Hence the new null point will be obtained at 300 cm.