What is the energy of a single photon of blue light with a wavelength of 488 nm (488 * 10-9 m) ?

E = hf

c = speed of electromagnetic wave, c ≈ 3 * 10⁸ m/s,

Planck's constant h = 6.63 * 10⁻³⁴ Js

h = Planck's constnat, Frquency, f = c/λ = (3*10⁸) / (488*10⁻⁹)

E = hf

E = hc/λ

E = (6.63 * 10⁻³⁴ * 3 * 10⁸) / (488 * 10⁻⁹)

Energy, E ≈ 4.0758 * 10⁻¹⁹ Joules.