× Home MCQ Videos Basic Electrical Circuit Theories Electrical Laws Materials Batteries Illumination Generation Transmission Distribution Switchgear Protection Measurement Control System Utilities Safety Transformer Motor Generator Electrical Drives Electronics Devices Power Electronics Digital Electronics Biomedical Instrumentation

Radiant Exitance and Luminous Exitance

Modified on Wednesday 27th of June 2018 at 07:37:28 PM

Radiant Exitance is defined as the radiant flux emitted from a source per unit area surface of that source.
Radiant flux is the source quantity. It is denoted as Me,λ and its unit is W/m2. One important thing is that radiance is related to the source whereas the irradiance is related to the detector. Both have same unit i.e. W/m2.

By applying Plank’s Law in the specific blackbody radiation, the radiant Exitance can be expressed as

You may also be interested on
Radiant Exitance and Luminous Exitance

Now we can define the Luminous Exitance and we can get Luminous Exitance by using the radiometric to photometric conversion equation. Where, Km is the constant which is called maximum spectral luminous efficacy and its value is 683 lm/W. So, the Luminous Exitance can be defined as the Luminous flux emitted from a source per unit surface area of that source. The unit of Luminous Exitance is lm/m2.

Radiant Intensity and Luminous Intensity

The energy flux per unit solid angle in certain direction is called radiant intensity. If the intensity is denoted by Here, ω is the solid angel in steradian and φλ is the energy flux at λ wavelength.

A filled detector with its active area is placed at r1 distance from a source and another detector with a different area is placed r2 in such a manner that they are in same solid angle. radiant intensity and luminous intensity The received flux by each other must be same. But in photometric, the luminous flux per unit solid angle in a given direction is called Luminous intensity. Its unit is Candela (Cd) or Lumen/steradian (lm/sr) The relation between the photometric and the radiometric intensity is given by Ie, λ is measured in W/sr and Iv is measured in lm/sr.

Rate the page


New Articles
ElectromyographyElectroretinographyIndoor SwitchgearEEG MeasurementElectroencephalography | EEG
Articles on Lux
Black Body RadiationPhotometry and RadiometryRadiant Flux and Luminous FluxIrradiance and IlluminanceRadiant and Luminous ExitanceRadiometric and PhotometricLaws of IlluminationTristimulus Values and Chromaticity CoordinatesTransmittance and ReflectanceRadiance and Luminance
More Articles on Illumination Engineering
LampsLighting SchemePhotometer
Articles Categories
MCQ Videos Basic Electrical Circuit Theories Electrical Laws Materials Batteries Illumination Generation Transmission Distribution Switchgear Protection Measurement Biomedical Instrumentation Control System Utilities Safety Transformer Motor Generator Electrical Drives Electronics Devices Power Electronics Digital Electronics Guest Post