We're asked to** calculate the energy of a photon** of wavelength 0.154 nm.

Recall that the energy of a photon is given by:

$\overline{){\mathbf{E}}{\mathbf{=}}{\mathbf{h\nu}}}$

▪E = energy = J

▪h = Planck's constant = 6.626x10^{-34} J∙s▪ν = frequency = Hz or s

*In the equation, the frequency of the photon is used but the wavelength is given. **We can relate frequency and wavelength using the speed of light:*

The relationship between wavelength and frequency is as follows:

$\overline{){\mathbf{\lambda}}{\mathbf{=}}\frac{\mathbf{c}}{\mathbf{\nu}}}$

▪* c = speed of light = 3.0x10 ^{8} m/s*▪ λ = wavelength, m

*Rearranging the above equation*:

$\overline{)\mathbf{c}\mathbf{=}\mathbf{\lambda}\mathbf{\xb7}\mathbf{\nu}}\phantom{\rule{0ex}{0ex}}\frac{\mathbf{c}}{\mathbf{\lambda}}\mathbf{=}\frac{\overline{)\mathbf{\lambda}}\mathbf{\xb7}\mathbf{\nu}}{\overline{)\mathbf{\lambda}}}\phantom{\rule{0ex}{0ex}}\overline{){\mathbf{\nu}}{\mathbf{=}}\frac{\mathbf{c}}{\mathbf{\lambda}}}$

Calculate the energy of a photon of wavelength 0.154 nm .