12th Class Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर Question Bank Case Based (MCQs) - Current Electricity

  • question_answer
    The temperature coefficient of the resistance of a wire is 0.00125 per\[{}^\circ C\]. At 300 K its resistance is 1 ohm. The resistance of wire will be 2 ohms at:

    A) 1154 K

    B) 1100 K

    C) 1400 K

    D) 1127K

    Correct Answer: D

    Solution :

    Using \[{{R}_{T}}={{R}_{0}}\left( 1+\alpha T \right)\]
    \[\therefore \,\,\,\frac{{{R}_{{{T}_{2}}}}}{{{R}_{{{T}_{1}}}}}=\frac{{{R}_{0}}\left( 1+\alpha {{T}_{2}} \right)}{{{R}_{0}}\left( 1+\alpha {{T}_{1}} \right)}=\frac{2}{1}=\frac{\left( 1+\alpha {{T}_{2}} \right)}{\left( 1+\alpha \times 300 \right)}\]
    \[\Rightarrow \,2+\alpha \times 600=1+\alpha {{T}_{2}}\]
    \[\Rightarrow \,1=\alpha \left( {{T}_{2}}-600 \right)\Rightarrow \frac{1}{0.00125}=\left( {{T}_{2}}-600 \right)\]
    \[\Rightarrow \,\,\,800{}^\circ C={{T}_{2}}-600\]
    \[{{T}_{2}}=800-273+600\]
    \[{{T}_{2}}=1127\,K\]


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