According to Einstein the energy of photon is given by the equation,
E = hν = h . c/λ
where h is Planck's constant, c is the speed of light, ν is the frequency of light and λ is the wavelength of light.
Given, wavelength of photon = 413 nm = 413 x 10⁻⁹ m
Conversion factor: 1 nm = 10⁻⁹ m
c = 3 x 10⁸ m/s
h = 6.626× 10⁻³⁴ J.s
Substituting the data into the equation we get,
E = h . c/λ
E = 6.626× 10⁻³⁴ J.s x (3 x 10⁸ m/s) / 413 x 10⁻⁹ m
E = 4.8 x 10⁻¹⁹ J
The energy of this blue light is 4.8 x 10⁻¹⁹ J