If a light ray passes from one medium into another medium, e.g. from air to water, the wave changes its direction, or its path is “bent”. This phenomenon is called light refraction.

The change of direction depends on the two media involved and on the angle at which the light approaches and departs from the boundary. Light waves passing through an acrylic cylinder also encounter boundaries. They are diffracted by the cylindrical form in such a way that the light radiation entering the cylinder forms parallel bundles.

Light refraction is affected by many optical elements.

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