JEE Main & Advanced Physics Current Electricity, Charging & Discharging Of Capacitors / वर्तमान बिजली, चार्ज और कैपेसिटर का निर Question Bank Electric Conduction Ohms and Resistance

  • question_answer
    The resistance of a conductor is 5 ohm at 50oC and 6 ohm at 100oC.  Its resistance at  0oC is            [KCET 2000]

    A)            1 ohm

    B)                                      2 ohm

    C)            3 ohm                                     

    D)            4 ohm

    Correct Answer: D

    Solution :

                 \[\frac{{{R}_{1}}}{{{R}_{2}}}=\frac{(1+\alpha {{t}_{1}})}{(1+\alpha {{t}_{2}})}\Rightarrow \frac{5}{6}=\frac{(1+\alpha \times 50)}{(1+\alpha \times 100)}\]\[\Rightarrow \alpha =\frac{1}{200}\text{ per}{{\text{ }}^{o}}C\] Again by \[{{R}_{t}}={{R}_{0}}(1+\alpha t)\]            \[\Rightarrow \,\,5={{R}_{0}}\left( 1+\frac{1}{200}\times 50 \right)\Rightarrow {{R}_{0}}=4\Omega .\]


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