JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर Question Bank Self Evaluation Test - Current Electricity

  • question_answer
    The charge flowing through a resistance R varies with time t as \[Q=at-b{{t}^{2}}.\] The total heat produced in R by the time current ceases is

    A) \[{{a}^{3}}R/6b\]

    B) \[{{a}^{3}}R/3b\]

    C) \[\frac{{{a}^{3}}R}{2b}\]

    D) \[\frac{{{a}^{3}}R}{b}\]

    Correct Answer: A

    Solution :

    [a] \[Q=at-b{{t}^{2}}\text{           }i=\frac{dQ}{dt}=a-2bt\] \[i=0\text{ for }t={{t}_{0}}=a/2b,\text{ i}\text{.e}\text{.,}\] current flow from The heat produced=\[\int\limits_{0}^{{{t}_{0}}}{{{i}^{2}}\,R\,dt.}\] Putting the value of I we get heat produced\[=\frac{{{a}^{3}}R}{6b}.\]


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