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JEE Main & Advanced Sample Paper JEE Main - Mock Test - 44

  • question_answer
    What should be the velocity of a \[{{e}^{-}}\]so that its momentum becomes equal to that of a photon of wavelength\[\text{5200}\overset{\text{o}}{\mathop{\text{A}}}\,\]?

    A) 700 m/s            

    B) 1000 m/s

    C) 1400 m/s    

    D)        2800 m/s

    Correct Answer: C

    Solution :

      [c] \[{{P}_{e}}={{P}_{ph}}\] \[mv=\frac{hc}{\lambda }\] \[v=\frac{hc}{\lambda \times m}\] \[=\frac{6.67\times {{10}^{-34}}\times 3\times {{10}^{8}}}{5200\times {{10}^{-10}}\times 9.1\times {{10}^{-31}}}\] \[\simeq \,1400m/s\]


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