NEET2003PhysicsAtomic PhysicsActual
Assertion : A tube light emits white light. Reason : Emission of light in a tube takes place at a very high temperature.
Options
- Aif both assertion and reason are true and the reason is the correct explanation of the assertion
- Bif both assertion and reason are true and the reason is not the correct explanation of the assertion
- Cif assertion is true but reason is false
- Dif both assertion and reason are false statements.
Correct answer
C. if assertion is true but reason is false
Step-by-step solution
The tube light is nothing but a gas discharge tube, which can emit light of different colours. This colour depends mainly upon the nature of the gas inside the tube and the nature of the glass. For neon gas the colour is bright red and for CO ₂ it is bluish. Again the fluorescent glow looks yellowish green for soda glass. So it is the nature of the glass and the gas inside the tube which determines the colour of the fluorescent glow. As argon is filled inside a tube light, the colour of the light is white.