A light bulb with a tungsten filament is attached to a source of variable voltage. As the voltage is increased on the bulb,
A) the bulb's resistance decreases.
B) the bulb's resistance increases.
C) the power dissipated remains constant.
D) the current in the bulb decreases.

Question

Quizplus · Accepted Answer

As the voltage increases, the filament's temperature rises, causing its resistance to increase due to the positive temperature coefficient of resistance of tungsten.

A Light Bulb with a Tungsten Filament Is Attached to a Source