Question

Two electric bulbs whose resistances are in the ratio 1: 3 are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio

• A. 1 :3
• B. 1 :1
• C. 3 :1
• D. 1 ;9

Answer 1

The correct option is C 3 :1

Power dissipated $P=\frac{V^2}{R}$

$⟹$ $P\propto \frac{1}{R}$ for same voltage

Given : $\frac{R_1}{R_2}=\frac{1}{3}$

$\therefore$ Ratio of power dissipated $\frac{P_1}{P_2}=\frac{R_2}{R_1}=3$