A power rating printed on a lightbulb assumes a voltage of 120 V is applied to the bulb. If two 100 W bulbs are connected in series to a 120 V source,
A) no current will pass through the bulbs.
B) each bulb radiates 100 W.
C) each bulb radiates more than 100 W.
D) each bulb radiates less than 100 W.

Question

Quizplus · Accepted Answer

When two bulbs are connected in series, the voltage is split between them, so each bulb receives only 60 volts. Using the power formula P = V^2 / R, we can calculate that each bulb will radiate (60^2 / 100) = 36 W. Therefore, each bulb radiates less than 100 W.

A Power Rating Printed on a Lightbulb Assumes a Voltage