Radiant flux Radiant flux In radiometry, radiant flux or radiant power is the radiant energy emitted, reflected, transmitted or received, per unit time, and spectral flux or spectral power is the radiant flux per unit frequency or wavelength, depending on whether the spectrum is taken as a function of frequency or of wavelength. The SI unit of radiant flux is the watt (W), that is the joule per second () in SI base units, while that of spectral flux in frequency is the watt per hertz () and that of spectral flux in wavelength is the watt per metre ()—commonly the watt
Cubic metre per second Cubic metre per second A cubic metre per second (ms, m/s, cumecs or cubic meter per second in American English) is a derived SI unit of volumetric flow rate equal to that of a stere or cube with sides of one metre (~39.37 in) in length exchanged or moving each second. It is popularly used for water flow, especially in rivers and streams, and fractions for HVAC values measuring air flow. The term cumec is also used, as shorthand for "Cubic metres per second", with the plural form "cumecs" also common in speech. It is commonly used between workers in