Question

An electron of mass m_e and a proton of mass $m_p$ are moving with the same speed. The ratio of their de-Brogile wave length $\left(\frac{{\lambda }_e}{{\lambda }_p}\right)$ is

• A. $981$
• B. $\frac{1}{1836}$
• C. $1836$
• D. $\frac{1}{381}$

Answer 1

The correct option is C $1836$

$\left(\frac{{\lambda }_e}{{\lambda }_p}\right)=\frac{h}{m_{e}V}\times \frac{m_{p}V}{h}=\frac{m_p}{m_e}=\frac{1.67\times {10}^{-27}}{9.1\times {10}^{-31}}=1836$