At a certain distance a from the uniformly luminous plane A there is an opaque screen B with a round hole of diameter d (Fig. 147). At the same distance a behind the screen B there is frosted glass C. Find the illumination of the central section of the frosted glass (point D), if it is known that the luminous plane emits light energy F in 1 second from 1 cm2 of surface per unit solid angle. Assume that the diameter holes d are significantly smaller than distance a.

Detailed solution. Format gif