Universal Inverse Square Law Display
The inverse square law display uses an illuminance meter and a moveable light source to demonstrate how footcandle level on a surface is inversely proportional to its distance from the source. The inverse square law is limited to a single point of analysis, and does not include reflected light in the space. It is most useful when working with very focused luminaire distributions.
This display also shows how to evaluate the angular relationship between the source and the surface.