Wavelength-Energy Relationship
Photon energy is inversely proportional to wavelength: shorter wavelength = higher energy
Energy Formula
E = hc / λ
E = hν
E (Joules)
Energy per photon
h = 6.626 × 10⁻³⁴ J·s
Planck's constant
c = 3.00 × 10⁸ m/s
Speed of light
Example Calculations
Example: Visible Light (550 nm)
λ = 550 nm = 550 × 10⁻⁹ m
E = (6.626 × 10⁻³⁴)(3.00 × 10⁸) / (550 × 10⁻⁹)
E = 3.61 × 10⁻¹⁹ J per photon
Green light photon energy
Example: X-ray (1.0 nm)
λ = 1.0 nm = 1.0 × 10⁻⁹ m
E = hc/λ = 1.99 × 10⁻¹⁶ J
550× more energetic than green light!