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 heating element has a resistance of \[100\Omega \]at room temperature. When it is connected to a supply of 220V, a steady current of 2A passes in it and temperature is\[500{{\,}^{o}}C\]more than room temperature. What is the temperature coefficient of resistance of the heating element?              [JEE Main Online 16-4-2018]

    A) \[1\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]

    B) \[5\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]

    C) \[2\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]

    D) \[0.5\times {{10}^{-4}}{{\,}^{o}}{{C}^{-1}}\]

    Correct Answer: C

    Solution :

    [c] We know that resistance
    \[R=\frac{V}{i}=\frac{220}{2}={{R}_{o}}(1+\alpha \Delta t)\]
    Also\[{{R}_{o}}\]is given as\[100\Omega \]
    Putting\[\Delta T=500\,K\]
    We get\[\alpha =2\times {{10}^{-4}}\]


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