Question

Light energy is obtained in fluorescent lamp and in CFL as a result of electron emission. Yet, the process of electron emission is different in both cases. What is the difference?

Answer 1

In a compact fluorescent lamp ( CFL ), the fast-moving electrons collide with the atoms of mercury vapour filled in the tube and emit invisible ultraviolet rays. The emitting power of electrons increases because of the coating of thorium oxide.
Working: Mercury gets evaporated and collides with the emitted electrons. Thus, ultraviolet rays are produced which are then absorbed by the fluorescent material in the lamp and changed into visible light.