Key Stage 3
Meaning
Refraction is when a wave changes direction as it moves from one medium to another.
About Refraction
- Waves travel in a straight line until they reach a new medium. If the wave can travel through the new medium it will change direction. This is called refraction.
- Refraction can happen to all waves.
Refraction of Light
- When light moves from one transparent medium to another it is refracted.
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| When a ray of light moves from air into water the ray is refracted towards the normal. | When a ray of light moves from water into air the ray is refracted away from the normal. |
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| When a ray of light moves from air into glass the ray is refracted towards the normal and when it moves from glass into air the ray is refracted away from the normal |
- Incident Ray - A ray is called an incident ray before it reaches the boundary between two media.
- Refracted Ray - Once the ray passes the boundary it is called a refracted ray.
- Normal - The normal line is an imaginary line drawn at right angles to the boundary between two media.
- Angle of Incidence - The angle between the Incident Ray and the Normal is called the angle of incidence.
- Angle of Refraction - The angle between the Refracted Ray and the Normal is called the angle of refraction.
- Emergent Ray - When a ray enters and then leaves a new medium the ray that leaves is called an emergent ray.