## power level

https://doi.org/10.1351/goldbook.P04793
Logarithm of the ratio of a @P04792@ to a reference @P04792@. Levels are expressed in different ways: $$L_{P}=\frac{1}{2}\ \ln (\frac{P}{P_{0}})\ \mathrm{Np}$$, where $$\mathrm{Np}$$ is the symbol for the unit @N04106@ coherent with the SI, or $$L_{P}=10\ \log _{10}(\frac{P}{P_{0}})\ \mathrm{dB}$$, where $$\mathrm{dB}$$ is the symbol for the unit @D01546@.
Source:
Green Book, 2nd ed., p. 79 [Terms] [Book]