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WB JEE Medical WB JEE Medical Solved Paper-2013

  • question_answer
    The value of Plancks constant is \[6.63\times {{10}^{-34}}\,Js.\]The speed of light is \[3\times {{10}^{17}}nm{{s}^{-1}}.\] Which value is closest to the wavelength in nanometer of a quantum of light with frequency of \[6\times {{10}^{15}}{{s}^{-1}}\]?

    A)  10

    B)  25

    C)  50

    D)  75

    Correct Answer: C

    Solution :

     Given, Plancks constant, \[h=6.63\times {{10}^{-34}}\,J-s\] Speed of light, \[c=3\times {{10}^{17}}\,nm\,{{s}^{-1}}\] Frequency of quanta \[v=6\times {{10}^{15}}{{s}^{-1}}\] Wavelength, \[\lambda =?\] We know that, \[v=\frac{c}{\lambda }\] or \[\lambda =\frac{c}{v}\] \[=\frac{3\times {{10}^{17}}}{6\times {{10}^{15}}}\] \[=0.5\times {{10}^{2}}\,nm\] \[=50\,nm\]


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