BCECE Medical BCECE Medical Solved Papers-2011

  • question_answer
    At \[{{127}^{o}}C\] radiated energy is \[2.7\times {{10}^{-3}}\] J/s. At what temperature radiated energy is \[4.32\times {{10}^{6}}\]J/s?

    A)  400 K         

    B)  4000 K

    C)  80000 K       

    D)  40000 K

    Correct Answer: C

    Solution :

    Energy radiated from a body                  \[Q=Ae\sigma {{T}^{4}}t\] \[\Rightarrow \] \[\frac{{{Q}_{2}}}{{{Q}_{1}}}={{\left( \frac{{{T}_{2}}}{{{T}_{1}}} \right)}^{4}}\] \[\Rightarrow \] \[\frac{{{T}_{2}}}{{{T}_{1}}}={{\left( \frac{{{Q}_{2}}}{{{Q}_{1}}} \right)}^{1/4}}={{\left( \frac{4.32\times {{10}^{6}}}{2.7\times {{10}^{-3}}} \right)}^{1/4}}\] \[\Rightarrow \] \[\frac{{{T}_{2}}}{400}={{\left( \frac{16\times 27}{27}\times {{10}^{8}} \right)}^{1/4}}=2\times {{10}^{2}}\] \[\Rightarrow \] \[{{T}_{2}}=-200\times 400=80000\,K\]


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