J & K CET Medical J & K - CET Medical Solved Paper-2014

  • question_answer
    A silver wire has a resistance of\[1.6\,\Omega \]. At \[25.5{}^\circ C,\]and a resistance of\[2.5\,\Omega \]. at\[100{}^\circ C,\]then temperature coefficient of resistivity of silver is

    A)  \[5.55\times {{10}^{-3}}{}^\circ C\]      

    B)  \[7.55\times {{10}^{-3}}{}^\circ C\]

    C)  \[11.75\times {{10}^{-2}}{}^\circ C\]     

    D)  \[15.5\times {{10}^{-3}}{}^\circ C\]

    Correct Answer: B

    Solution :

     \[{{R}_{2}}={{R}_{1}}[1+\alpha ({{T}_{2}}-{{T}_{1}})]\] \[\frac{({{R}_{2}}-{{R}_{1}})}{({{T}_{2}}-{{T}_{1}})}\times \frac{1}{{{R}_{1}}}=\alpha \] \[\frac{(2.5-1.6)}{(100-25.5)}\times \frac{1}{1.6}=\alpha \] \[\frac{0.9}{74.5}\times \frac{1}{1.6}=\alpha \] \[0.0075503=\alpha \] \[\alpha =7.55\times {{10}^{-3}}{}^\circ C\]


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