JEE Main & Advanced Sample Paper JEE Main Sample Paper-46

  • question_answer
    The average translational energy and the \[rms\]speed of molecules in a sample of oxygenate 300K are \[6.21\times {{10}^{-21}}J\] and 484 m/s, respectively. The corresponding values at 600Kare nearly (assuming ideal gas behavior).

    A)  \[12.42\times {{10}^{-21}}J,\,\,968\,\,m/s\]

    B)  \[6.21\times {{10}^{-21}}J,\,968\,m/s\]

    C)  \[8.78\times {{10}^{-21}}J,\,684\,\,m/s\]

    D)  \[12.42\times {{10}^{-21}}J,\,\,684\,\,m/s\]

    Correct Answer: D

    Solution :

     As \[KE=\frac{3}{2}\,kT\] and \[{{V}_{rms}}=\sqrt{\frac{3RT}{M}}\] \[\therefore \]    \[K{{E}_{2}}=2K{{E}_{1}}=2\times 6.21\times {{10}^{-21}}\] \[=12.42\times {{10}^{-21}}J\] \[\frac{{{V}_{rms,\,\,2}}\,}{{{V}_{rms,\,\,1}}}=\sqrt{\frac{{{T}_{2}}}{{{T}_{1}}}}=\sqrt{2}\] \[\therefore \]    \[{{V}_{rms,\,\,2}}=\sqrt{2}\times {{V}_{rms,\,\,1}}\] \[=684\,\,m/s\]


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