A potentiometer wire PQ of 1 m length is connected to a standard cell . Another cell of emf 1.02 V is connected with a resistance ‘r’ and switch S (as shown in figure). With switch S open, the null position is obtained at a distance of 49 cm from Q. The potential gradient in the potentiometer wire is:
As switch S is open
Under balancing condition, no current flows through secondary circuit.
So
(Pot. gradient)
(Pot. gradient)