In the figure, the potentiometer wire AB is 40 cm long. Where must the free end of the galvanometer be connected on AB for the galvanometer to show zero deflection?

Step-by-step solution

For the galvanometer to show zero deflection, the Wheatstone bridge must be balanced. Let the balancing length from point A be l . Since the total length of the wire is 40 cm , the remaining length is (40 - l) . Using the balanced Wheatstone bridge principle: 8 12 = l 40 - l 2 3 = l 40 - l 3l = 80 - 2l 5l = 80 l = 16 cm