How does the intensity of light decrease a function of thedistance?

Principle

For the setup and performance of the experiment it is important that the room is darkened and that the solar cell is orientated in such a way that it can pick up only a small amount of stray light. (This means that in the classroom the solar cells should point towards the walls so that the students do not interfere with one another.) The solar cell is in part covered with cardboard so that the reference area for the (almost) perpendicular incident light is equal. If the entire solar cell is used the angles of incidence are very different if the solar cell is close to the light source.

Benefits

• Specified for the requirements of the german final secondary-school examinations
• Especially for secondary schools
• Quantum and wave optics in a student experiment

Tasks

How does the brightness of light change with increasing distance? When one moves away from a light source it becomes darker. Everybody knows this. In this experiment you will derive a relationship between the distance from a light source and the light intensity.