Question

A metal rod consumes power P on passing current. If it is cut into two halfs and joined in parallel, it will consume what power?

Answer 1

Answer:

Explanation:

Let the resistance of the rod be R. If the rod is divided into two equal parts, then each part of the rod will have a resistance of R/2. Now these two parts of the rod are connected in parallel and a voltage V is applied across them. Hence the total power consumed is P = V2/R  is the power consumed by the original rod  when voltage V is applied across it.

Answer 2

Answer:

4P

Explanation:

Upon cutting it into two halves, resistance becomes half. The equivalent resistance is now 1/4 of original.

Since power is inversely proportional to resistance, the answer is 4P