Total reflection and the critical angle

Principle

With total reflection the students become acquainted with an important special case of the law of reflection, when light passes from an optically denser to an optically less dense medium, which has a special importance for technology (fibre-optic cables).
In this experiment, the students should first become familiar with the known phenomenon of refraction when light passes from glass to air, but their attention is to be directed to the region within the block and thus to the increasing reflection of light.
In an additional procedure they observe and investigate the case in which light hits the boundary between glass and air at an angle which is smaller than the critical angle for total reflection.

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 does the term "total reflection" mean? Investigate the behaviour of narrow light beams when light passes from glass to air with an angle of incidence greater than 40°.