Potentiometer has multiple uses. It is based on the principle that when constant current flows through a wire of uniform area of cross-section then potential drop along its length is directly proportional to corresponding length.

i.e.  $V \propto I$

$V=K I$

Various uses of potentiometer on:

• To measure potential differences between any two points in an electrical network
• To compare emf of a cell
• To measure emf of a cell
• To measure internal resistance of a cell etc.

Answer the following question related to potentiometer:

In the given potentiometer on increasing value of R:

Balancing length will increases

The correct answer is Option (2) → Balancing length will increases

On increasing the value of R, the current decreases. Hence to obtain the same balancing length larger resistance of potentiometer wire would be needed.

Hence balancing length will increase.