# 2.6    Find energy of each of the photons which  (ii) have wavelength of 0.50 Å.

For the wavelength $\lambda = 0.50\times10^{-10}m$.
$E = h\vartheta = \frac{hc}{\lambda} = \frac{(6.626\times10^{-34}J.s)\times(3\times10^{15}s^{-1})}{0.50\times10^{-10}m} = 3.98\times10^{-15}J$