Light Reflection & Refraction

Test yourself on Light Reflection & Refraction

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Reflection of Light

Light can be reflected by a plane (flat surface).

Angle of incidence

The angle of incidence is the angle between the incident (incoming) light ray and the normal.
The normal is a line at 90 degrees to the plane.

Angle of reflection

The angle of reflection is the angle between the reflected light ray and the normal.

Law of reflection

The law of reflection states that the angle of incidence = the angle of reflection.

Refraction of Light

Light is refracted when it travels from one medium to another and changes speed.

Optically dense materials

If light slows down as it enters a new medium, this medium is “more optically dense”.
When light enters a more optically dense medium, it is refracted closer to the normal.
This means that the angle of refraction is smaller than the angle of incidence.

Less optically dense materials

If light speeds up on entering a new medium, this medium is “less optically dense”.
The light is refracted further from the normal - the angle of refraction is larger than the angle of incidence.

Angle of Refraction

The angle of refraction is the angle between the refracted light ray and the normal.

More optically dense material

When light enters a more optically dense medium, it is refracted closer to the normal and the angle of refraction is smaller.

Less optically dense

When light travels from one medium and to a less optically dense medium, it is refracted further away from the normal and the angle of refraction is larger.