Question

Two bulbs A and B rated 100W-120V and 10W-120V respectively to a 120V source in series. Which one of them will consume more energy?​

Answer 1

QuesTion :-

Two bulbs A and B are rated 100 W − 120 V and 10 W − 120 V respectively. They are connected across a 120 V source. Find the current in each bulb. Which bulb will consume more energy ?

SoluTion :-

$\sf { Resistance \ of \ bulb \ A \ \{R_{1}\} =\frac{V^{2}}{P^{1}} =\frac{120^{2}}{100 \ W} =144 \Omega }\\\\\\\sf { Resistance \ of \ bulb \ A \ \{R_{2}\} =\frac{V^{2}}{P^{2}} =\frac{120 \ V^{2}}{10 \ W} =1440 \Omega }\\\\\\\\\sf {Current \ through \ bulb \ A \ \{I_{1}\}=\frac{V}{R_{1}} =\frac{120 \ V}{144 \Omega} =0.83A}\\\\\\\sf {Current \ through \ bulb \ A \ \{I_{2}\}=\frac{V}{R_{2}} =\frac{120 \ V}{1440 \Omega} =0.083A}$

Thus, Bulb A (100 W) will consume more energy than the bulb A (10 W)