Module 01 · Physics of light
The Visible Spectrum
Visible light occupies a narrow band of the electromagnetic spectrum — between about 380 and 750 nanometers. Drag the slider to traverse it, and watch wavelength, frequency, and photon energy interlock.
550nm
380450500550600650750
Green
#A3FF00
Why this color?
A photon at 550 nm oscillates roughly 545 trillion times per second and carries about 2.25 eV of energy. When it strikes the retina, it stimulates a particular combination of three cone types, which the brain interprets as the hue you see in the swatch.
λ
550 nm
ν
545 THz
E
2.25 eV