# 17-24-062

Lambert's cosine law

Lambert's law for a surface element whose radiance or luminance is the same in all directions of the hemisphere above the surface

Note 1 to entry: Lambert's cosine law can be expressed by
I(θ) = Icosθ
where I(θ ) and In are the radiant intensities or luminous intensities of the surface element in a direction at an angle, θ, from the normal to the surface and in the direction of that normal, respectively.

Note 2 to entry: This entry was numbered 845-04-56 in IEC 60050-845:1987.

Note 3 to entry: This entry was numbered 17-632 in CIE S 017:2011.

Publication date: 2020-12