Radiant Intensity

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radiant intensity

[′rād·ē·ənt in′ten·səd·ē]
The energy emitted per unit time per unit solid angle about the direction considered; usually expressed in watts per steradian.

Radiant Intensity


a radiometric unit that characterizes the radiation from a source in a certain direction. Radiant intensity is equal to the ratio of the radiant flux emitted by the source in an infinitesimal solid angle containing the direction considered to the solid angle. The concept of radiant intensity is applicable at distances from the source that greatly exceed the source’s dimensions. The unit of radiant intensity is watts per steradian.

References in periodicals archive ?
The first term represents the spectral emission from the surface, while the second term represents the reflected radiant intensity.
A typical radiant intensity of 650 mW/sr at a DC current of 1 A (4232).
While standard IR emitters typically offer drive currents to 100 mA, the low thermal resistivity of the VSLB9530S allows continuous drive currents up to 150 mA, which pushes the achievable radiant intensity to 60 mW/sr at 150 mA.
12] hertz and that has a radiant intensity in that direction of 1/683 watts per steradian.
In remote control operation, the transceiver features wide transmission angle (30 degrees minimum) and high radiant intensity (40 mW/sr typical) to make it easy to aim.
The instrument is suitable for luminous or radiant intensity measurements, tunnel brightness, total luminous or radiant flux measurements, device brightness, signal brightness, and equipment and device illumination measurements.
And for small angles of roughly three degrees, values of up to 700 mW/steradiant (measuring the radiant intensity of sharply focusing infrared emitting diodes) can be achieved, even with a small chip.
The company's processing technique accommodates fabrication of pixels 25 microns square with radiant intensity of 25 [micro]W to 75 [micro]W per steradian at 3 mA depending on wavelength.
Infrared radiant intensity can be hazardous to the human eye if it does not fall within specified safe limits, and a warning label is mandated if a product fails to meet the IEC standard.