2. Solved Papers
  3. AMU Medical

AMU Medical AMU Solved Paper-2011

  • question_answer
    The number density of free electrons in a copper conductor is \[8.5\times {{10}^{28}}.\,{{m}^{-3}}\] How long does an electron take to drift from one end of a wire 3.0 m long to its other end? The area of cross-section of the wire is \[2.0\times {{10}^{-6}}{{m}^{2}}\]and it is carrying a current of 3.0A.

    A) \[8.1\times {{10}^{4}}s\]                              

    B)  \[2.7\times {{10}^{4}}s\]

    C)  \[9\times {{10}^{3}}s\]                                

    D)  \[3\times {{10}^{3}}s\]

    Correct Answer: B

    Solution :

                     Given,                  \[l=3.0\]                 \[A=2.0\times {{10}^{-6}}{{m}^{2}}\]                 \[i=30\,A\]                 \[{{v}_{d}}=\frac{i}{neA}\] \[{{v}_{d}}=\frac{3}{8.5\times {{10}^{28}}\times 1.6\times {{10}^{-19}}\times 2\times {{10}^{-6}}}\] \[{{v}_{d}}=1.10\times {{10}^{-4}}\] Time \[t=\frac{l}{{{v}_{d}}}=\frac{3}{1.10\times {{10}^{-4}}}\]                 \[2.7\times {{10}^{4}}s\]


You need to login to perform this action.
You will be redirected in 3 sec spinner