JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank Photon and Photoelectric Effect

  • question_answer
    The number of photons of wavelength 540 nm emitted per second by an electric bulb of power 100W is (taking h = \[6\times {{10}^{-34}}\,J\text{-}sec\]) [Kerala (Engg.) 2002; Pb. PET 2001]

    A)            100

    B)            1000

    C)            \[3\times {{10}^{20}}\]    

    D)            \[3\times {{10}^{18}}\]

    Correct Answer: C

    Solution :

               \[p=\frac{nhc}{\lambda t}\Rightarrow 100=\frac{n\times 6\times {{10}^{-34}}\times 3\times {{10}^{8}}}{540\times {{10}^{-9}}\times 1}\]Þ\[n=3\times {{10}^{20}}\]


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