Which process involves light emission due to a passing current heating a gas?

The correct answer involves the process known as electric discharge, which specifically pertains to light emission that occurs when an electric current passes through a gas. When the current flows, it energizes the gas molecules, exciting them to higher energy states. As these excited molecules return to their ground state, they release energy in the form of light. This process is commonly observed in neon signs and other gas discharge lamps, where the passing current causes the gas to glow.

The distinction between electric discharge and other processes lies in the requirement of an electric current to excite the gas. This is what makes electric discharge unique compared to other processes that produce light. Fluorescence, for instance, involves the absorption of light and subsequent re-emission, rather than the application of electric current. Incandescence refers to light produced by heating a solid object until it glows, while triboluminescence is light generated by mechanical action, such as the breaking or rubbing of certain materials. Hence, electric discharge specifically describes the phenomenon where light is emitted directly due to an electric current interacting with a gas.