Refraction
Physics: IB Diploma Higher Level, topic 3.4.3
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, light is refracted closer to the normal.
- The angle of refraction is smaller.
Less optically dense
- Light travels from one medium to a less optically dense medium.
- Light is refracted further away from the normal.
- The angle of refraction is larger.
Test yourself on Refraction
What happens to the angle of refraction when light enters a less optically dense medium and speeds up?
Which of these is true about refraction?
A ray of light travels from air into a glass block. Glass is more optically dense than air. What happens to the angle of refraction as the light enters the glass?
What happens when the critical angle of incidence is exceeded?
What are the conditions for total internal reflection?