Question

A wire when connected to 220V mains supply has power dissipation $P_{1}$. Now the wire is cut into two equal pieces which are connected in parallel to the same supply. Power dissipation in this case is $P_{2}$. Then $P_{2}:P_{1}$ is

• A. 1
• B. 4
• C. 2
• D. 3

Answer 1

Answer: (B)

4

Answer 2

When wire is cut into two equal parts then power dissipated by each part is $2P_{1}$So their parallel combination will dissipate power

$P_{2} = 2P_{1} + 2P_{1} = 4P_{1}$ Which gives $\frac{P_{2}}{P_{1}} = 4$