A 60-W light bulb and a 100-W light bulb are each rated at 120 V.Which light bulb has a larger resistance?
A)the 60-W bulb
B)the 100-W bulb
C)Both have the same resistance.

Question

Quizplus · Accepted Answer

The power dissipated by a resistor (such as a light bulb) is given by P = V^2/R, where V is the voltage across the resistor and R is the resistance. Since both bulbs are rated at the same voltage, the bulb with the higher power rating (100 W) must have a lower resistance than the bulb with the lower power rating (60 W), in order to dissipate more power (P = V^2/R). Thus, the 60-W bulb has the larger resistance.

A 60-W Light Bulb and a 100-W Light Bulb Are