Q. 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
Explanation
(b) 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 $\frac{P_{2}}{P_{1}} = 4$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.