Respuesta :

E=hf

h = Planck's constant (6,626.10⁻³⁴ Js)

f = c / λ

E= (6,626.10⁻³⁴ x 3 x 10⁸)/4 x 10⁻⁷

E = 4.97 x 10⁻¹⁹ J