valgusallikast lähtuva, antud suunda sisaldavas ruuminurgaelemendis dW leviva valgusvoo dF ja nimetatud ruuminurgaelemendi jagatis
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Ühik: kandela, cd; 1 cd = 1 lm×sr –1 = 1 lm/sr .
quotient of the luminous flux, dFv, leaving the source and propagated in the element of solid angle dΩ containing the given direction, by the element of solid angle
