Unformatted text preview: .61 Diamond 124,000 2.42 Polymethylmethacrylate (PMMA) 200,000 1.49 Table 11.4.1: Speed of light and refractive index 11.4.1 Reflection
The following principle applies with regard to reflection of light:
Angle of incidence = Angle of reflection
Here the angles are measured between the vertical and the angle of incidence. α α Fig. 11.4.2: Reflection of light beams © Festo Didactic GmbH & Co. KG • FP 1110 187 11. Physical fundamentals 11.4.2 Refraction
At the interface of two transparent media a light beam is not only reflected, but part
of its energy overspills in a different direction in the new medium, i.e. it is refracted.
Here, a medium with reduced speed of light propagation is known as optically
denser and that which is greater as optically thinner.
With the transition from an optically thinner to an optically denser medium, the
angle of refraction is smaller than the angle of incidence, the beam is refracted
towards the vertical.
With the transition from an optically denser to an optically thinner medium, the
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