Photon energy (Forλ=1m)
=6.63×10−34×3×1081.6×10−19eV=1.24×10−6eV
Photon energy for other wavelengths in the figure for electromagnetic spectrum can be obtained by multiplying approximate powers often. Energy of a photon that a source produces indicates the spacings of the relevant energy levels of the source. For example, λ=10−12 corresponds to photon energy =1.24×106eV=1.24MeV This indicates that nuclear energy levels (transition between which causes γ-ray emission) are typically spaced by 1 MeV or so. Similarly, a visible wavelength λ=5×10−7m, corresponds to photon energy= 2.5 eV. This implies that energy levels (transition between which gives visible radiation) are typically spaced by a few eV.