Question

State the principle of a potentiometer. Define potential gradient. Obtain an expression for potential gradient in terms of resistivity of the potentiometer wire.

Answer 1

It is based on the fact that the fall of potential across any segment of the wire is directly proportional to the length of the segment of the wire, provided wire is of uniform area of cross-section and a constant current is flowing through it.V∝ l

Potential gradient is the fall of potential per unit length of potentiometer wire. 

Potential gradient