G9 Wave Model - Bending Light

Gapfill exercise

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   along      bounce      boundary      critical      dispersion      normal      reflected      spectrum      speeds   
Light is refracted when it passes from one mdeium to another. This is because the light changes speed.

Total Internal Reflection
If light travels from a 'slower' medium into a 'faster' medium it gets bent away from the , which means towards the between the two media.
If you keep increasing the angle at which it hits the boundary, it will reach a point where the ray passing out of the first medium travels the boundary. This is known as the angle. If you keep on increasing the angle at which the ray hits the boundary, the ray will be back from it. This is called total internal reflection (TIR).

Optical fibres use total internal reflection. The light ray hits the inside boundary of the fibre at an angle greater than the critical angle and gets reflected back. It continues to all the way along the inside of the fibre.

Dispersion
Different wavelengths of light travel at different through glass. This is used in where a glass prism is used to produce a of colours.