If the momentum of an electron is changed by $p$, then the de-Broglie wavelength associated with it changes…
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
$200 p$
$400 p$
$\frac{p}{200}$
$100 p$
Solution
de-Broglie wavelength
Here
$\begin{aligned}
\lambda & =\frac{h}{p} \\
\left|\frac{\Delta \lambda}{\lambda}\right| & =\left|\frac{\Delta p}{p}\right| \\
\frac{0.5}{100} & =\frac{p}{p_i} \\
p_i & =\frac{100}{0.5} p \\
p_i & =200 p
\end{aligned}$