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JCECE Engineering JCECE Engineering Solved Paper-2009

  • question_answer
    The energy of a photon is\[3\times {{10}^{-12}}erg\]. What is its wavelength in\[nm\]?       \[(h=6.62\times {{10}^{-27}}erg-s;\,\,c=3\times {{10}^{10}}cm/s)\]

    A) \[66.2\]                               

    B) \[1324\]

    C)  \[66.2\]                                              

    D)  \[6.62\]

    Correct Answer: A

    Solution :

    \[E=3\times {{10}^{-12}}erg\]                 \[\lambda =?\]                 \[h=6.62\times {{10}^{-27}}erg\text{-}s\]                 \[c=3\times {{10}^{10}}cm{{s}^{-1}}\]                 \[E=\frac{hc}{\lambda }\]                 \[3\times {{10}^{-2}}=\frac{6.62\times {{10}^{-27}}\times 3\times {{10}^{10}}}{\lambda }\]                 \[\lambda =\frac{6.62\times {{10}^{-27}}\times 3\times {{10}^{10}}}{3\times {{10}^{-12}}}\]


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