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 \[1\Omega \]. The resistance of wire will be \[2\,\Omega \] at                        

    A) 1154 K

    B) 1100 K  

    C) 1400 K                         

    D) 1127 K        

    Correct Answer: D

    Solution :

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


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