JEE Main & Advanced Physics Alternating Current / प्रत्यावर्ती धारा JEE PYQ-Alternating Current

  • question_answer
    The AC voltage across a resistance can be measured using a:        [JEE MAIN 11-04-2015]

    A) potentiometer

    B) moving coil galvanometer

    C) moving magnet galvanometer

    D) hot wire voltmeter

    Correct Answer: D

    Solution :

    [d] In a potentiometer, the null point will fluctuate due to varying current & voltage.
    In the moving magnet /coil galvanometer, the dial will be unsteady due to varying current through it.
    In hot wire voltmeter, the principle of heat due to current is used to measure the voltage.
    \[{{P}_{avg}}=\frac{V_{RMS}^{2}}{R}\]                    \[\therefore \]\[V_{RMs}^{2}=R\,{{P}_{avg}}\]
    \[\therefore \]\[\]


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