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JEE Main & Advanced Physics Photo Electric Effect, X- Rays & Matter Waves Question Bank Self Evaluation Test - Dual Nature of Radiation and Matter

  • question_answer
    An electron of mass 'm' and charge 'e' initially at rest gets accelerated by a constant electric field E. The rate of change of de-Broglie wavelength of this electron at time t, ignoring relativistic effects is:

    A) \[\frac{-h}{eE{{t}^{2}}}\]

    B) \[\frac{-eht}{E}\]

    C) \[\frac{-mh}{eE{{t}^{2}}}\]

    D) \[\frac{-h}{eE}\]

    Correct Answer: A

    Solution :

    [a] Acceleration, \[a=\frac{Ee}{m}\] Velocity of electron, \[v=at=\frac{Eet}{m}\] Wavelength, \[\lambda =\frac{h}{mv}=\frac{h}{Eet}.\] Now   \[\frac{d\lambda }{dt}=-\frac{h}{eE{{t}^{2}}}\]


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