Find the number of photons of wavelength ${\lambda }_1=5.0\times {10}^{-5} \mathrm{cm}$ whose total energy is equal to the energy of one photon of wavelength ${\lambda }_2=2.0\times {10}^{-12} \mathrm{cm}$. In which part of the electromagnetic spectrum do ${\lambda }_1$ and ${\lambda }_2$ fall?