Mammoth Memory

Normal line - Flat surfaces

We have later a great way to remember the normal line. But for now we will just explain what the normal line is in relation to rays of light entering a flat surface.

The normal line is an imaginary line perpendicular (at 90°) to where the ray of light touches the boundary.

For a ray of light travelling from air to water the refraction would be:

Refraction of a ray of light as it travels from air into water.

 and for a ray of light travelling from water to air the refraction would be:

Refraction of ray of light travelling from water to air.

 

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