Q. An electron of mass $m_{e}$and a proton of mass $m_{p}$ are moving with the same speed. The ratio of their de-Brolie wavelength $\lambda_{e}/\lambda_{p}$ is
A) 918
B) $\frac{1}{1836}$
C) 1836
D) 1
Explanation
(c) ${\frac{\lambda_{e}}{\lambda_{p}} - \frac{\frac{h}{m_{e}V}}{\frac{h}{m_{p}V}} = \frac{m_{p}}{m_{e}}
}{= \frac{1.67 \times 10^{- 27}}{9.1 \times 10^{- 31}}}$
$= 0.18 \times 10^{4} = 1836\ \ \ \ $
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.