The circuit below contains three 100-W light bulbs and a capacitor. The emf ε = 110V. At the instant the switch S is closed, which light bulb is brightest?
A)A
B)B
C)C
D)A and B
E)All three are equally bright.

Question

The circuit below contains three 100-W light bulbs and a capacitor. The emf ε = 110V. At the instant the switch S is closed, which light bulb is brightest? 
A)A 
B)B 
C)C 
D)A and B 
E)All three are equally bright.

Quizplus · Accepted Answer

When the switch S is closed, the capacitor acts as a short circuit, allowing the current to flow through all three light bulbs in parallel. Since all three light bulbs have the same resistance and are connected in parallel with the same voltage across them, they will all have the same brightness. Therefore, the answer is choice C, "All three are equally bright."

The Circuit Below Contains Three 100-W Light Bulbs and a Capacitor