Question

The ratio of the energy of a photon of $2000A^0$ wavelength radiation to that of $4000A^0$ of radiation is?

Answer 1

$E=hc/\lambda$

ratio of energy of photon $\frac{E_1}{E_2}=\frac{{\lambda }_2}{{\lambda }_1}=\frac{4000}{2000}=\frac{2}{1}$