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NEET Sample Paper NEET Sample Test Paper-29

  • question_answer
    For a black body at temperature \[{{727}^{o}}C,\] its radiating power is 60 watt and temperature of surrounding is\[{{227}^{o}}C\]. If temperature of black body is changed to \[{{1227}^{o}}C\] then its radiating power will be :-

    A)  304 W                        

    B)  320 W

    C)  240 W                        

    D)  120 W

    Correct Answer: B

    Solution :

    \[P\propto ({{T}^{4}}-{{T}_{0}}^{4})\] \[\frac{{{P}_{2}}}{{{P}_{1}}}=\frac{{{(1500)}^{4}}-{{(500)}^{4}}}{{{(1000)}^{4}}-{{(500)}^{4}}}=\frac{{{500}^{4}}({{3}^{4}}-1)}{{{500}^{4}}({{2}^{4}}-1)}\] \[\frac{{{P}_{2}}}{60}=\frac{80}{15}\]   \[\Rightarrow \]   \[{{P}_{2}}=320\,W\]


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