In electric discharge lamps, the light is produced through the process of ionization in a gas or vapor. This phenomenon occurs due to the flow of electric current through the lamp.

Explanation:
- Electric discharge lamps, such as fluorescent lamps, neon lamps, and sodium vapor lamps, work on the principle of ionization. These lamps contain a gas or vapor-filled chamber with two electrodes, known as a cathode and an anode.
- When a high voltage is applied across the electrodes, it creates an electric field within the lamp. This electric field causes the gas or vapor molecules to become excited and gain energy.
- As the energy level of the gas or vapor molecules increases, some of the electrons in the outermost orbit of the atoms get detached from their parent atoms, creating free electrons.
- These free electrons collide with other gas or vapor molecules, causing further ionization. This process continues, leading to a chain reaction of ionization and the release of more free electrons.
- As the free electrons return to their original energy levels, they emit photons of light. This light emission occurs at specific wavelengths, depending on the type of gas or vapor present in the lamp.
- Different gases or vapors emit different colors of light. For example, neon gas emits red light, while mercury vapor emits blue or ultraviolet light.
- The photons emitted by the ionized gas or vapor create visible light, which is observed as the illumination of the lamp.
- The intensity and color of the light produced by the lamp can be controlled by varying the gas or vapor composition and the voltage applied to the electrodes.

In summary, the light in electric discharge lamps is produced through the process of ionization in a gas or vapor. The flow of electric current through the lamp causes the gas or vapor molecules to become excited and release photons of light as the electrons return to their original energy levels. This phenomenon allows electric discharge lamps to produce visible light for various applications.