Question

A uniform wire is cut in two pieces such that one piece is twice as long as the other.the two pieces are connected in parallel in left Gap of a metre-bridge.when a resistance of 20 ohm is connected in the right Gap the null point is obtained at 60cm from the right end.find resistance of wire before it was cut into two pieces​

Answer 1

Answer:

Explanation:

The resistance of a wire depends directly on the length of a wire. thus if we reduce the length of a wire to half the resistance too will drop to half.

thus now two pieces will have 10 ohm resistance each

thus let equivaent resistance in parallel connection be Rq :

Thus 1/Rq = 1/10 +1/10

Rq = 10/2 =5 ohm