SSC General Science & Technology Sample Paper NCERT Sample Paper-3

  • question_answer
    The most commonly used substances in florescent tubes are

    A)  Sodium vapour and neon

    B)  Sodium oxide and argon

    C)  Mercury vapour and argon

    D)  Mercury oxide and neon

    Correct Answer: C

    Solution :

    [c] A fluorescent lamp or a fluorescent tube is a low pressure mercury-vapour gas-discharge   lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapour which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow. A fluorescent lamp converts electrical energy into useful light much more efficiently than incandescent lamps.

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