joule

Radiance (L)- light carried by a ray from a light source. 1 Watt(W) = 1 Joule per second. A radian(r) is a measure of an angle, a steradian/ square radian[(sr) is a measure of a solid angle. e.g. In a cone it’s the amount of the radian area of the cone. IrradianceContinue Reading