Punjab Medical Punjab - MET Solved Paper-2009

  • question_answer
    A wire\[50cm\]long and\[1m{{m}^{2}}\]in cross-section carries a current of\[4A\]when connected to a \[2\,\,V\]battery. The resistivity of the wire is

    A) \[2\times {{10}^{-7}}\Omega \,\,m\]                     

    B) \[5\times {{10}^{-7}}\Omega \,\,m\]

    C) \[4\times {{10}^{-6}}\Omega \,\,m\]                     

    D) \[1\times {{10}^{-6}}\Omega \,\,m\]

    Correct Answer: D

    Solution :

    Resistivity of a wire is given by                 \[\rho =\frac{RA}{l}\]                                     ? (i)                 \[l=50\,\,cm=0.50\,\,m\]                 \[A=1m{{m}^{2}}={{10}^{-6}}{{m}^{2}}\] From Eq. (i), we get \[\therefore \]  \[\rho =\frac{0.5\times {{10}^{-6}}}{0.50}=1\times {{10}^{-6}}\Omega \,\,m\]


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