A proton has kinetic energy $\mathrm{E}=100\mathrm{k}\mathrm{e}\mathrm{V}$ which is equal to that of a photon. The wavelength of photon is ${\lambda }_2$ and that of proton is ${\lambda }_1$. The ratio of ${\lambda }_1/{\lambda }_2$ is proportional to

The energy of a photons is equal to the kinetic energy of a proton. If ${\lambda }_1$ is the de-Broglie wavelength of a proton, ${\lambda }_2$ the wavelength associated with the photon, and if the energy of the photon is E, then $({\lambda }_1/{\lambda }_2)$ is proportional to: