Question:
An electron of mass $m$ and a photon have same energy E. The ratio of wavelength of electron to that of photon is: (c being the velocity of light)
Correct Option: , 2
Solution:
$\lambda_{1}=\frac{\mathrm{h}}{\sqrt{2 \mathrm{mE}}}$
$\lambda_{2}=\frac{\mathrm{hc}}{\mathrm{E}}$
$\frac{\lambda_{1}}{\lambda_{2}}=\frac{1}{\mathrm{c}}\left(\frac{\mathrm{E}}{2 \mathrm{~m}}\right)^{1 / 2}$