A mercury street light gets brighter as it warms up because
A) the voltage across it is increasing.
B) the liquid mercury is flowing around more, making better connections.
C) more mercury is vaporizing.
D) it is getting darker outside and so it just looks brighter.

Question

Quizplus · Accepted Answer

As the mercury street light warms up, more mercury vaporizes. The increased amount of mercury vapor allows for more efficient discharge processes, which in turn produces more light. This is why the light gets brighter as it warms up.

A Mercury Street Light Gets Brighter as It Warms Up