P14 Flashcards
What can all waves be?
Absorbed,transmitted or reflected
When a wave arrives at a boundary between two different materials what happens?
- The waves are absorbed by the material the wave is trying to cross into this transferes the energy to the material energy stores
- The waves are transmitted. Refraction happens
- The waves are reflected
Angle of incidence =
Angle of reflection
Whats the angle of incidence?
The angle between the incoming line and normal
Whats the angle of reflection?
The angle between the reflected and the normal
Whats the normal line?
An imaginary line perpindicular to the surface at the point of incidence. Normally the dotted line
When does specular reflection happen?
A wave is reflected in a single direction by a smooth surface.
Give an example of specular reflection?
When light is reflected in the mirror and you get a clear reflection
What is diffuse reflection?
When a wave is reflected by a rough surface and the rays are scattered in different directions
What happenes when loght is reflected by a rough surface?
The surface appears matte and you don’t get a clear reflection of objects
What’s refraction?
Waves changing direction at a boundary
What happens when a wave crosses a boundary at an angle and changes direction?
It refracts
What does how much it refracts depend on?
- How much it speeds up or slows down
- Also density of 2 materials
What does a higher density mean?
It will slow down
What happens when a wave crosses a boundary and slows down?
It will bend towards the normal line
What happens if it crosses into another material and speeds up?
Bend away from the normal line
What happens when the wavelength of a wave stays the same?
The frequency stays the same
What happens if a wave travels across the normal line?
Change speed but not refract
Why do waves go in a different direction?
The wave hit a medium
Whats the optical density?
A measure of How quickly light can travel through it
What does higher the optical density mean?
The slower light waves travel through it
Why should you do the practical in a dim room?
So you can see the light rays better