Which process is associated with the emission of light during fire?

The process associated with the emission of light during fire is combustion. Combustion is a chemical reaction in which a fuel reacts with an oxidizer, usually oxygen, resulting in the release of energy in the form of heat and light. This exothermic reaction involves the breaking of molecular bonds and the formation of new substances, typically gases such as carbon dioxide and water vapor, along with the characteristic flame. The light emitted during combustion is primarily due to the excitation of molecules and the release of energy as they return to their normal state, producing visible light in the form of flames.

In contrast, pyrolysis refers to the thermal decomposition of materials at elevated temperatures in an oxygen-free environment, which produces flammable gases and can occur before combustion. Ignition is the initial phase that initiates fire, whereas smoke production is a result of incomplete combustion, containing solid particles and gases, but it does not directly relate to the emission of visible light like combustion does.