Wavelength, Frequency and Energy of Light

Frequency units are Hertz (Hz), or cycles/second, or s-1 c = speed of light in a vacuum c = 3.00 x 108 meters/second

h = Planck's Constant = 6.626 x 10-34 J·s This is the energy of one PHOTON. A photon acts like a little bullet of energy. It is a particle and a wave at the same time. So just as MATTER is "quantized" into ATOMS, LIGHT and ENERGY are quantized into PHOTONS and QUANTA. The perceived INTENSITY or brightness of a light depends on how many PHOTONS PER SECOND hit your eye. The ENERGY of the photon depends on its wavelength. Sunscreen is used to absorb the high energy UV photons that can cause skin cancer, while letting the photons of visible light come through.