Q. Two electric bulbs, one of $200\ volt\ 40\ watt$ and the other $200\ volt\ 100\ watt$ are connected in a house wiring circuit
A) They have equal currents through them
B) The resistance of the filaments in both the bulbs is same
C) The resistance of the filament in $40\ watt$ bulb is more than the resistance in $100\ watt$ bulb
D) The resistance of the filament in $100\ watt$ bulb is more than the resistance in $40\ watt$ bulb
Explanation
(c) $P = \frac{V^{2}}{R} \Rightarrow R_{1} = \frac{V_{1}^{2}}{P_{1}} = \frac{(200)^{2}}{40} = 1000\Omega$
and $R_{2} = \frac{V_{2}^{2}}{P_{2}} = \frac{(200)^{2}}{100} = 400\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.