1. Electricity Flows: When you flip the switch, electricity flows through the tube's electrodes at each end.
2. Electron Emission: The electrodes heat up and release electrons (a process called thermionic emission).
3. Ionization: These electrons collide with the gas atoms inside the tube (usually mercury vapor and argon). This collision causes some of the gas atoms to lose electrons and become positively charged ions.
4. Plasma Formation: The mixture of electrons and ions creates a plasma – a superheated, electrically conductive gas.
5. Ultraviolet Light Emission: The energized electrons in the plasma recombine with the ions, releasing energy in the form of ultraviolet (UV) light.
6. Phosphor Coating: The inside of the fluorescent tube is coated with phosphors. These substances absorb the invisible UV light and re-emit it as visible light.
In Summary: The electrical current creates a plasma inside the tube, which emits ultraviolet light. This light is then converted into visible light by the phosphor coating, giving us the bright, cool white light we associate with fluorescent lamps.
