In radiometry, radiant intensity is a measure of the intensity of electromagnetic radiation. It is defined as power per unit solid angle. The SI unit of radiant intensity is Watts per steradian (W·sr^-1). It is distinct from intensity defined by irradiance or radiant exitance which measure radiation directed at or emitted from a given surface area.

See also

• Candela
• Luminous intensity
• Intensity

Radiometry | Physical quantity

放射強度