What phenomenon may occur in voids and other gas pockets within electrical equipment?

The correct choice is related to the phenomenon known as corona discharge, which can occur in voids and gas pockets within electrical equipment. When electrical equipment operates under high voltages, the presence of gas pockets can lead to ionization of the gas. This ionization creates a conductive path for electricity, resulting in partial discharges that manifest as a glow or hissing sound around the electrical components. The corona effect is particularly relevant in high-voltage environments, where these discharges can lead to energy losses and potential damage to the insulation and other components.

In contrast, other phenomena listed, such as arcing, cavitation, and condensation, do not specifically relate to the presence of voids or gas pockets within electrical equipment in the same context. Arcing typically refers to a more intense electrical discharge across a gap, whereas cavitation involves the formation and collapse of vapor bubbles in liquids, a situation not pertinent to gas pockets in electrical equipment. Condensation involves the transition of a substance from a gas to a liquid, which of course can occur in various environments, but does not specifically relate to the electrical behavior of gas pockets under high voltage conditions.