If wavelength of radiation is 4000 A° = 400 nm then the energy of the photon is

Q: If wavelength of radiation is 4000 A° = 400 nm then the energy of the photon is

Sol: $\large E = \frac{h c}{\lambda} = \frac{12400}{4000 A^o} eV$ 

E = 3.1 eV