JEE Main & Advanced Chemistry Structure of Atom / परमाणु संरचना Question Bank Self Evaluation Test - Structure of Atom

  • question_answer
    The values 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 \[8\times {{10}^{15}}{{s}^{-1}}\]?

    A) \[5\times {{10}^{-18}}\]     

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

    C) \[3\times {{10}^{7}}\]        

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

    Correct Answer: B

    Solution :

    [b] \[E=hv=\frac{ch}{\lambda };\,and\,v=\frac{c}{\lambda }\]                 \[8\times {{10}^{15}}=\frac{3.0\times {{10}^{8}}}{\lambda }\] \[\therefore \lambda =\frac{3.0\times {{10}^{8}}}{8\times {{10}^{15}}}=0.37\times {{10}^{-7}}\] \[=37.5\times {{10}^{-9}}m=4\times {{10}^{-1}}nm\]


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