Question

Two cells of emfs approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm.(a) The battery that runs the potentiometer should have voltage of 8V(b) The battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the wire slightly exceeds 10 V(c) The first portion of 50 cm of wire itself should have a potential drop of 10 V(d) Potentiometer is usually used for comparing resistances and not voltages

Answer 1

Answer:

To measure potential of 10V the minimum voltage of source should be slightly greater than 10V hence answer is C.