up:: [[Radiation]] The radiative energy emitted from a surface per unit area is called Emissive Power, *E* *Total emissive power* is flux radiated in all wavelengths J/s/m^2 *Spectral emissive power* is flux radiated at a specific wavelength J/s/m^2/$\micro$m Wavelength is denoted in microns(1e-6m) or nanometer(1e-9m) or frequently in Angstroms Å (1e-10m). *Monochromatic emissive power* is the flux at a single wavelenght