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NEET Sample Paper NEET Sample Test Paper-68

  • question_answer
    There is a current of 40 ampere in a wire of \[{{10}^{-6}}\,{{m}^{2}}\] area of cross-section. If the number of free electron per \[{{m}^{3}}\,is\text{ }{{10}^{29}}\], then the drift velocity will be

    A) \[1.25 \times  1{{0}^{3}}m/s\]  

    B) \[2.50 \times  1{{0}^{-}}^{3}m/s\]

    C) \[25.0 \times  1{{0}^{-}}^{3}m/s\]

    D) \[250 \times  1{{0}^{-}}^{3}m/s\]

    Correct Answer: B

    Solution :

    \[{{V}_{d}}=\frac{i}{neA}=\frac{40}{{{10}^{29}}\times {{10}^{-6}}\times 1.6\times {{10}^{-19}}}\] \[=\,\,\,2.5\times {{10}^{-3}}\,m/s.\]


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