Planck Constant

**Semantic type:** Quantitative Concept

**Definition:** A fundamental physical constant in quantum mechanics such that the energy of a photon is equal to its frequency multiplied by the Planck constant (h), and the wavelength of a matter wave equals h divided by the associated particle momentum. This constant is expressed in SI units and h equals 6.62607015 x 10^-34 joules per Hertz.

**Synonyms:** - Planck constant - Planck constant - [h] - [h] - h