JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर JEE PYQ-Current Electricity Charging and Discharging of Capacitors

  • question_answer
    A particle of mass M is moving in a circle of fixed radius R in such a way that its centripetal acceleration at time t is given by \[{{n}^{2}}R\,{{t}^{2}}\] where n is a constant. The power delivered to the particle by the force acting on it, is:[JEE ONLINE 10-04-2016]

    A) \[M\,\,n\,{{R}^{2}}\,{{t}^{2}}\]

    B) \[\frac{1}{2}M{{n}^{2}}{{R}^{2}}{{t}^{2}}\]

    C) \[M\,{{n}^{2}}{{R}^{2}}t\]

    D) \[M\,n\,{{R}^{2}}\,t\]

    Correct Answer: C

    Solution :

    [c] \[\frac{{{V}^{2}}}{R}={{n}^{2}}R{{t}^{2}}\]
    \[\Rightarrow {{V}^{2}}={{n}^{2}}{{R}^{2}}{{t}^{2}}\]
    \[\Rightarrow V=nRt\]
    \[\Rightarrow \frac{dV}{dt}=nR\]
    \[P={{F}_{t}}V\]
    \[m=\frac{mdV}{dt}V\]
      \[=mnR.\,nRt\]
    \[P={{n}^{2}}{{R}^{2}}t\,m\]


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