Application of Gas Discharge Tube

Fluorescence Lamp:

The principle of the gas discharge tube is used in fluorescent tubes for lighting and display of signs.

The tube contains mercury or sodium vapour which glows at very low pressure at the passage of cathodeA cathode is the electrode from which a conventional current leaves the electrolyte. It is the negative part of the cell where reduction takes place. More rays. The cathode rays cause the emission of ultraviolet rays when they bombard the mercury vapour. The interior of the fluorescent tube is coated with phosphorus, which gives off visible light when hit by ultraviolet rays.

The colour of light produced in a fluorescent tube depends on:

1. Nature of the gas in the tube.
2. Nature of the coatings in the tube.

Fluorescent tubes are used as display signs and they are more efficient than filament lamps. Neon gases are mostly used in the tubes which always produce an orange or red colour.