Medium MCQ +4 / -1 PYQ · JEE Mains 2021

An electron having de-Broglie wavelength $\lambda$ is incident on a target in a X-ray tube. Cut-off wavelength of emitted X-ray is :

  1. A 0
  2. B ${{2{m^2}{c^2}{\lambda ^2}} \over {{h^2}}}$
  3. C ${{2mc{\lambda ^2}} \over h}$ Correct answer
  4. D ${{hc} \over {mc}}$

Solution

$\lambda = {h \over {mv}}$<br><br>kinetic energy, $${{{P^2}} \over {2m}} = {{{h^2}} \over {2m{\lambda ^2}}} = {{hc} \over {{\lambda _c}}}$$<br><br>${\lambda _c} = {{2mc{\lambda ^2}} \over h}$

About this question

Subject: Physics · Chapter: Dual Nature of Matter and Radiation · Topic: Photoelectric Effect

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