An electron of mass
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:

1. (1) 918

2. (2) 1836

3. (3) $\frac{1}{1836}$

4. (4) 1

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

$\lambda=\frac{h}{p}=\frac{h}{m v}$

$\frac{\lambda_{e}}{\lambda_{p}}=\frac{m_{p}}{m_{e}}$

$=\frac{1836 \mathrm{~m}_{e}}{\mathrm{~m}_{e}}$

$\frac{\lambda_{e}}{\lambda_{p}}=1836$