a) On what principle does lighting in a fluorescent tube operate? (b) State two factors which determine the colour of light produced in a fluorescent tube.
Question 1 Report
a) On what principle does lighting in a fluorescent tube operate?
(b) State two factors which determine the colour of light produced in a fluorescent tube.
Answer Details
(a) Principle of the fluorescent tube
A fluorescent tube works on the principle of gas discharge and fluorescence. When a high voltage is applied, electrons flow through the low-pressure mercury vapour in the tube, exciting the mercury atoms; these emit ultraviolet radiation. The ultraviolet light strikes the fluorescent (phosphor) coating on the inside of the tube, which absorbs it and re-emits the energy as visible light (fluorescence).
(b) Two factors determining the colour of the light produced
- The nature (chemical composition) of the phosphor / fluorescent powder coating the inside of the tube.
- The type of gas or vapour (and its pressure) contained in the tube.
Download The App On Google Playstore
Everything you need to excel in your exams
