High voltage power lines are usually supported by glass insulators. An electric current cannot flow through a piece of glass because
A) glass contains only positively charged particles.
B) glass contains only negatively charged particles.
C) the electrons in the glass completely fill its valence levels and can't shift from one level to another to transport charge through the glass.
D) glass does not contain any electrically charged particles.

Question

Quizplus · Accepted Answer

Glass is an insulator because its electrons are tightly bound within its atomic structure, filling the valence levels so they cannot move freely to conduct electricity.

High Voltage Power Lines Are Usually Supported by Glass Insulators