Question

A major line in an atomic emission spectrum occurs at $450$ nm. Find the energy decrease, as this photon is emitted.

Answer 1

Energy decrease as the photon is emitted is given by:

$E=hv=\frac{hc}{\lambda }=\frac{6.626\times {10}^{-34}Js\times 3\times {10}^{8}m{s}^{-1}}{450\times {10}^{-9}m}=4.417\times {10}^{-19}J$