NEET Sample Paper NEET Sample Test Paper-37

  • question_answer
    Two identical metal balls at temperature \[\text{200 }\!\!{}^\circ\!\!\text{ C}\] and \[\text{400 }\!\!{}^\circ\!\!\text{ C}\] kept in air at\[\text{27 }\!\!{}^\circ\!\!\text{ C}\]. The ratio of net heat loss by these bodies is

    A)  1/4            

    B)  1/2

    C)  1/16

    D)  \[\frac{{{473}^{4}}-{{300}^{4}}}{{{673}^{4}}-{{300}^{4}}}\]

    Correct Answer: D

    Solution :

     If temperature of surrounding is considered,  then net loss of energy of a body by radiation \[Q=A\varepsilon \sigma ({{T}^{4}}-T_{0}^{4})t\Rightarrow Q\propto ({{T}^{4}}-T_{0}^{4})\] \[\Rightarrow \] \[\frac{{{Q}_{1}}}{{{Q}_{2}}}=\frac{T_{1}^{4}-T_{0}^{4}}{T_{2}^{4}-T_{0}^{4}}\] \[=\frac{{{(273+200)}^{4}}-{{(273+27)}^{4}}}{{{(273+400)}^{4}}-{{(273+27)}^{4}}}\] \[=\frac{{{(473)}^{4}}-{{(300)}^{4}}}{{{(673)}^{4}}-{{(300)}^{4}}}\]


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