| 释义 |
planck radiation law
noun
Usage: usually capitalized P
Etymology: after Max K. E. L. Planck
1. : a law in physics: radiant energy arising from processes within atoms or molecules is emitted in finite quanta each of which is equal to the product of the radiation frequency by a universal constant h — see planck constant
2. : a law in physics: the energy density of radiation within a blackbody cavity at absolute temperature T in terms of the wavelength λ is given by ΔPλ = (8πhc)/(λ5[ehc/(KλT) - 1]) Δλ where ΔPλ is the energy density within a given small wavelength interval Δλ, h is the Planck constant, and c the speed of light, all quantities being in cgs units |