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
    In a wire of circular cross-section with radius r, free electrons travel with a drift velocity V when a current I flows through the wire. What is the current in another wire of half the radius and of the same material when the drift velocity is 2V          [MP PET 1997]

    A)                    2I

    B)                                      I

    C)                    \[I/2\]                             

    D)            \[I/4\]

    Correct Answer: C

    Solution :

                 From \[{{v}_{d}}=\frac{i}{neA}\Rightarrow i\propto {{v}_{d}}A\Rightarrow i\propto {{v}_{d}}{{r}^{2}}\]


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