Question

Why in potentiometer the emf of the cell which we have to calculate is less than the other cell?

Answer 1

Dear Student,

Because the max. potential difference across the resistance wire of potentiometer is the emf of driver cell. Thus emf's to be measured will be balanced in between the extreme points of the resistance wire of potentiometer only if their emf is less than the emf of driver cell. Thus potential drop across that wire and hence emf of driver cell must be more than the emf to be measured. If EMF of the driver is less than the e.m.f.s of each of cells whose emf is to be measured then null point or balanced point cannot be obtained.

Regards.