AIIMS AIIMS Solved Paper-2011

  • question_answer
    The rate of dissipation of heat by a black body at temperature T is Q. What will be the rate of dissipation of heat by another body at temperature 2 T and emissiviry 0.25?

    A)  16 Q                                     

    B)  4Q                        

    C)  8Q                        

    D)         4.5 Q

    Correct Answer: B

    Solution :

    By Stefens law \[=\frac{3\times 2\times 5000\times {{10}^{-10}}}{0.2\times {{10}^{-3}}}\] The rate of dissipation of heat by a body emissivity e is given by \[=\frac{6\times 5\times {{10}^{-7}}}{2\times {{10}^{-4}}}\] Here   \[=15mm=1.5cm\] and \[C=\frac{{{\varepsilon }_{0}}A}{d}\] \[=\frac{8.854\times {{10}^{-12}}\times 5\times {{10}^{-4}}}{0.885\times {{10}^{-2}}}=0.5pF\] \[=8C=8\times 0.5=4pF\]  Q = 0.25 x o(2 T)4


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