Q89 / 120 · NEET 2012 (Mains) · Physics

If the momentum of an electron is changed by $p$, then the de-Broglie wavelength associated with it changes by $0.5 \%$. The initial momentum of electron will be

  • Correct answer
    A
    $200 p$
  • B
    $400 p$
  • C
    $\frac{p}{200}$
  • D
    $100 p$

Solution

de-Broglie wavelength Here $$ \begin{aligned} \lambda & =\frac{h}{p} \\ \left|\frac{\Delta \lambda}{\lambda}\right| & =\left|\frac{\Delta p}{p}\right| \\ \frac{0.5}{100} & =\frac{p}{p_i} \\ p_i & =\frac{100}{0.5} p \\ p_i & =200 p \end{aligned} $$

Hence, the correct answer is option: 'A'.

Relevant Questions