An incandescent lightbulb is rated at 100 watts when plugged into a 110 V rms household outlet. Calculate the resistance of the filament and the rms current.
A)12.2 Ω, 0.91 A (rms)
B)10 Ω, 1.0 A (rms)
C)110 Ω, 1.0 A (rms)
D)121 Ω, 0.91 A (rms)
E)11 Ω, 1.1 A (rms)

Question

Quizplus · Accepted Answer

Using the formula P = V rms^2/R, we can find the resistance of the filament: R = V rms^2/P = (110 V)^2/100 W = 121 Ω.

Then, we can use the formula I rms = V rms/R to find the rms current: I rms = 110 V/121 Ω = 0.91 A.

Therefore, the correct answer is D, with a resistance of 121 Ω and an rms current of 0.91 A.

An Incandescent Lightbulb Is Rated at 100 Watts When Plugged