Q. The circuit shown here is used to compare the emf of two cells $E_{1}\ $and$E_{2}(E_{1} > E_{2})$. The null point is at $C$ when the galvanometer is connected to $E_{2}$. when the galvanometer is connected to $E_{2}$, the null point will be

A) To the left of $C$
B) To the right of $C$
C) At $C$ itself
D) None where on $AB$
Explanation

(a) $E_{1}E_{2} = l_{1}/l_{2}$. As, $E_{1}/E_{2}$, therefore $l_{1} > l_{2}$. Therefore the null point for thr cell of emf $E_{2}$must be at shorter length than that of cell $E_{1}.$Thus null point on potentiometer wire should shift towards left of $C$.

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.