What is the wavelength (in nm) of a photon if the energy is 7.13 × 10⁻¹⁹ J?

Answer 1

The equation we can use for this is

E = hc / λ

E = energy = 7.13x10^-19 J

h = Planck's constant = 6.626x10^-34 Js

c = speed of light = 3x10⁸ m/s

λ = wavelength in meters = ?

Solving for λ:

λ = hc / E = (6.626x10^-34 Js)(3x10⁸ m/s) / 7.13x10^-19 J

λ = 2.79x10^-7 m

Converting this to nm we have

2.79x10^-7 m x 1 nm / 10^-9 m = 279 nm (answer)