Photon Energy Formula

Photon energy is the energy possessed by a photon. The photon is the basic particle of light. Photons are massless, and photons are always moving at the speed of light in a vacuum. Photon energy varies directly with the frequency or the wavelength.

Formula 

The Photon energy formual is given by,

 E = hc/λ

Where

E = photon energy,

h = Planck's constant (6.626×10−34 Js)

c = speed of the light and

λ = wavelength of the light.

Solved Problems 

Example 1: Find the photon energy if the wavelength is 650nm.

Solution:

Given parameters are

λ = 650nm

c = 3×108×108m/s

h = 6.626×10−34×10−34Js

Photon energy formula is given by,

E = hc / λ

E = 6.626×10−34 ×3×108 / 650×10−9

E = 19.878 x 1028 / 650×10−9

E = 0.030 x 10−17J

Example 2: Calculate the wavelength of a photon of energy of 350×10−10J.

Solution: