Q. The three resistances of equal value are arranged in the different combinations shown below. Arrange them in increasing order of power dissipation
A) III < II < IV <I
B) II < III < IV < I
C) I < IV < III < II
D) I < III < II < IV
Explanation
(a) $P = i^{2}R$
Current is same, so $P \propto R$
In the first case I is $3r,$ in second case it is $\frac{2}{3}\ r,\ $ in third case it is $\frac{r}{3}\ $and in fourth case the net resistance is $\frac{3r}{2}.$
$R_{III} < R_{II} < R_{IV} < R_{I}$
$\therefore P_{III} < P_{II} < P_{IV} < P_{I}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.