Planck constant (J*s)
Planck described radiation emission as discrete packets, quantas, of energy. Planck's constant (denoted h) relates the wavelength to the frequency of an emission. The constant defines the quantum of action in physics.
Planck's constant is expressed in this equation in units of Joule seconds (J•s)
Planck's theory asserted that energy was transferred in units known as quanta in the ratio employed in Plank's Equation.is:
Note the following relations are also true:
by the , the measurements produced a final value of h of 6.626070150 × 10-34 kg?m2/s, with an uncertainty of 10 parts per billion. If the SI is redefined as expected in November of 2018, this will be the exact value of Planck’s constant which will define other SI units including the kilogram.
See, a discussion provided by NIST of the application of uncertainty to the documented constants.
Interested in the physicist for whom this constant is named? See Socratica's video on