question_answer

A potentiometer circuit shown in the figure is set up to measure e.m.f. of a cell E. As the point P moves from X to Y the galvanometer G shows deflection always in one direction, but the deflection decreases continuously until Y is reached. In order to obtain balance point between X and Y it is necessary to

A)                    Decreases the resistance R

B)                    Increase the resistance R

C)                    Reverse the terminals of battery V

D)                    Reverse the terminals of cell E