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NEET Sample Paper NEET Sample Test Paper-72

  • question_answer
    There is a current of 1.344 amp in a copper wire whose area of cross-section normal to the length of the wire is 1 mm. If the number of free electrons per \[c{{m}^{3}}\] is \[8.4 \times  1{{0}^{22}}\], then the drift velocity would be

    A) 1.0 mm/sec                   

    B) 1.0 m/sec

    C) 0.1 mm/sec                   

    D) 0.01 mm/sec

    Correct Answer: C

    Solution :

    \[{{v}_{d}}=\frac{i}{nAe}=\frac{1.344}{{{10}^{-\,6}}\times 1.6\times {{10}^{-19}}\times 8.4\times {{10}^{22}}}\] \[=\,\,\frac{1.344}{10\times 1.6\times 8.4}\,\,=\,\,0.01\,cm/s=0.1\,\,mm/s\]


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