Illuminance (inverse square law)

Principle

This experiment is suitable as both an introductory experiment and as a confirmation experiment for the validity of the inverse square law. In connection with the measurements of the side lengths of the illuminated areas the students must use their knowledge of umbra and penumbra. Since the light source is not a point, the marginal shadows are not sharply defined.

Benefits

• Multifunctional light box - All-in-one: Can be used for geometric optics on the table, colour mixing and on an optical bench
• Extension with others sets at anytime, no additional light sources needed, recognition value for students

Tasks

What is the correlation between the illumination and the distance from the light source to the illuminated area? Investigate how the illumination E is correlated with the separation r by changing the distance between a light source and an illuminated area.