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

  • question_answer A constant voltage is applied between the two ends of a metallic wire. If both the length and the radius of the wire are doubled, the rate of heat developed in the wire [MP PMT 1996]

    A)            Will be doubled                  

    B)            Will be halved

    C)            Will remain the same       

    D)            Will be quadrupled

    Correct Answer: A

    Solution :

                       \[H\propto \frac{1}{R}\] (If V = constant) Þ \[\,\frac{{{H}_{1}}}{{{H}_{2}}}=\frac{{{R}_{2}}}{{{R}_{1}}}\]\[=\frac{{{l}_{2}}{{A}_{1}}}{{{l}_{1}}{{A}_{2}}}\]\[=\frac{{{l}_{2}}r_{1}^{2}}{{{l}_{1}}r_{2}^{2}}\] Þ \[{{H}_{2}}=2{{H}_{1}}\]


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