gs1medium
Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury used in the manufacture of these lamps?
- A.A mercury coating on the inside of the lamp makes the light bright white
- B.When the lamp is switched on, the mercury in the lamp causes the emission of ultra-violet radiations
- C.When the lamp is switched on, it is the mercury which converts the ultra-violet energy into visible light
- D.None of the statement given above is correct about the use of mercury in the manufacture of fluorescent lamps
▶ Answer & Explanation
Correct answer: B. When the lamp is switched on, the mercury in the lamp causes the emission of ultra-violet radiations
Fluorescent lamps operate by passing an electric current through a gas mixture containing mercury vapor. This electrical discharge excites the mercury atoms, causing them to emit ultraviolet (UV) radiation. This UV radiation then strikes a phosphor coating on the inside of the glass tube, which absorbs the UV and re-emits it as visible light.
Source: UPSC gs1 2010