BCECE Medical BCECE Medical Solved Papers-2001

  • question_answer
    The specific resistance of wire of length 1 m, area of cross-section 0.5 \[{{m}^{2}}\] is \[25\,\,\mu \,\Omega \], The resistance of the wire will be :

    A)  \[5\times {{10}^{-5}}\Omega \]

    B)  \[3\times {{10}^{6}}\Omega \]

    C)  \[46\times {{10}^{6}}\Omega \]

    D)  \[2\times {{10}^{6}}\Omega \]

    Correct Answer: A

    Solution :

    Resistance R of a given conductor, at a constant temperature, is directly proportional to its length and inversely proportional to its area of cross-section A. i.e.,        \[R\propto \frac{1}{A}\] or \[R=\rho \frac{1}{A}\] where \[\rho \] is called the specific resistance of the material. Given, \[\rho =25\times {{10}^{-6}}\Omega m,\,\,l=1\,\,m,\,\,A=0.5\,{{m}^{2}}\] \[\therefore \] \[R=\frac{25\times {{10}^{-6}}\times 1}{0.5}\]                 \[=50\times {{10}^{-6}}\] \[=5\times {{10}^{-5}}\Omega \]


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