Question:
An electron of mass $m_{e}$ and a proton of mass $m_{p}=1836 m_{e}$ are moving with the same speed. The ratio of their de Broglie wavelength
$\frac{\lambda_{\text {himene }}}{\lambda_{\text {temown }}}$ will be:
Correct Option: , 2
Solution:
(2)
Given mass of electron $=\mathrm{m}_{e}$
Mass of proton $=\mathrm{m}_{\mathrm{p}}$
$\therefore$ given $m_{p}=1836 \mathrm{~m}_{\mathrm{e}}$
From de-Broglie wavelength
$\lambda=\frac{h}{p}=\frac{h}{m v}$
$\frac{\lambda_{e}}{\lambda_{p}}=\frac{m_{p}}{m_{e}}$
$=\frac{1836 \mathrm{~m}_{e}}{\mathrm{~m}_{e}}$
$\frac{\lambda_{e}}{\lambda_{p}}=1836$