JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors Question Bank Heating Effect of Current

  • question_answer According to Joule's law, if the potential difference across a conductor having a material of specific resistance remains constant, then the heat produced in the conductor is directly proportional to                                     [MP PMT 1986]

    A)            \[\rho \]                                 

    B)            \[{{\rho }^{2}}\]

    C)            \[\frac{1}{\sqrt{\rho }}\] 

    D)            \[\frac{1}{\rho }\]

    Correct Answer: D

    Solution :

               \[P=\frac{{{V}^{2}}}{R}\] but \[R=\frac{\rho l}{A}\] Þ \[P=\frac{{{V}^{2}}}{\rho l/A}=\frac{A{{V}^{2}}}{\rho l}\]. Since \[\frac{A{{V}^{2}}}{l}\]is constant as per given conditions So \[P\propto \frac{1}{\rho }.\]

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