Radiant intensity

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Radiant intensity (of a source, in a given direction)

Quotient of the radiant flux (dFe) leaving the source, propagated in an element of solid angle (dO) containing the given direction, by the element of solid angle.

Symbol Ie

Unit watt per steradian (W/sr)

Reference: C.I.E. (modified)

Note: 1 If within a finite solid angle O the radiant flux may be considered uniformly distributed, then the radiant intensity is given by ?? where Fe is the total radiant flux emitted within the solid angle.

Note: 2 The above definition strictly applies only to a point source. For a source which is not a point source see C.I.E.

Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)

English