Q. A photon and an electron (mass $m$) have the same energy $E$. The ratio $(\lambda_{photon}/\lambda_{electron})$ of their de Broglie wavelengths is ($c$ is the speed of light)
A) $\sqrt{E/2m}$
B) $c\sqrt{2mE}$
C) $c\sqrt{\frac{2m}{E}}$
D) $\frac{1}{c}\sqrt{E/2m}$
Explanation
[Solution by Claude - not from source] $\lambda_{ph}=\frac{hc}{E}$, $\lambda_e=\frac{h}{\sqrt{2mE}}$. Ratio $=\frac{c\sqrt{2mE}}{E}=c\sqrt{\frac{2m}{E}}$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.