The wavelength and the spectral region for a single electron transfer across the band gap in a semi-conductor $\left(\mathrm{E}_{\mathrm{x}}=1.98 \times 10^{-19}\right)$ are $\left[\mathrm{h}=6.626 \times 10^{-34}\,\mathrm{Js}, \mathrm{c}=3 \times 10^{8}\,\mathrm{ms}^{-1}\right]$