The laws of illumination are.
a. Illumination ‘E’ is directly proportional to the luminous intensity ‘I’ of the source. ie E ∝ I.
b. Inverse square law: The illumination of the surface is inversely proportional to the square of the distance of the surface from the source. ie E ∝ 1/d2 .
c. Illumination ‘E’ is directly proportional to the cosine of angle made by the normal to the illumination surface and the direction of the incident light and is known as lam pod’s cosine angle.