Easy MCQ +4 / -1 PYQ · JEE Mains 2020

A particle moving with kinetic energy E has de Broglie wavelength $\lambda$. If energy $\Delta$E is added to its energy, the wavelength become $\lambda$/2. Value of $\Delta$E, is :

  1. A E
  2. B 3E Correct answer
  3. C 2E
  4. D 4E

Solution

$\lambda = {h \over {\sqrt {2mE} }}$ <br><br>Also, ${h \over {\sqrt {2m\left( {E + \Delta E} \right)} }}$ = ${\lambda \over 2}$ <br><br>$\therefore$ ${{E + \Delta E} \over E} = 4$ <br><br>$\Rightarrow$ $\Delta$E = 3E

About this question

Subject: Physics · Chapter: Dual Nature of Matter and Radiation · Topic: de Broglie Hypothesis

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