JEE Main & Advanced Chemistry Structure of Atom Question Bank Critical Thinking

  • question_answer The value of Planck?s constant is \[6.63\times {{10}^{-34}}Js.\] The velocity of light is \[3.0\times {{10}^{8}}\,m{{s}^{-1}}\]. Which value is closest to the wavelength in nanometres of a quantum of light with frequency of  \[8\times {{10}^{15}}{{s}^{-1}}\]                                    [CBSE PMT 2003]

    A)                 \[3\times {{10}^{7}}\]   

    B)                 \[2\times {{10}^{-25}}\]

    C)                 \[5\times {{10}^{-18}}\]               

    D)                 \[4\times {{10}^{1}}\]

    Correct Answer: D

    Solution :

               \[\lambda =\frac{c}{v}=\frac{3\times {{10}^{8}}}{8\times {{10}^{15}}}=3.75\times {{10}^{-8}}\]                                   \[=3.75\times {{10}^{-8}}\times {{10}^{9}}nm\]\[=4\times {{10}^{1}}nm\].


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