Planck constant

Max Planck, after whom the Planck constant is named

The Planck constant, sometimes called Planck's constant, is an important number in quantum physics. It is named after the physicist Max Planck. It was first used as a way to link the amount of energy a photon carries with the frequency of its electromagnetic wave. This idea can be written in an equation like this $E=H \times F$ where E stands for energy, H is the Planck constant and F is the frequency.

The Planck constant can roughly be measured as 6.63x10⁻³⁴. Using this number scientists have calculated measurements like the Planck length, and the Planck time.