How to measure an unknown voltage using potentiometer.

Explain the method of measuring internal resistance using a potentiometer.

Potentiometer is used to

Potentiometer is used to

How the emf of two cells are compared using potentiometer ?

Volymeter can not be used to measure emf to a cell potentiometer can be used to measure emf of a cell because

State the working principle of potentiometer explain with the help of circuit diagram how the emf of two primary cells are compared by using the potentiometer.