P5- Waves Flashcards
What do waves transfer
Waves transfer engery but not matter
On a displacement distance graph what does displacement show
How far from the equilibrium point (the middle) the wave has oscillated
How is the amplitude measured on a displacement distance graph
The maxium displacement from the equilibrium
What is wavelength
The distance of one oscillation of a wave
Where do you measure wavelength on a wave
- From ‘crest’ to ‘crest’ (the peaks)
- From the equilibrium (up down and back up)
What is freaquency measured in
Hz
Hertz
What is freaquency
The number of complete oscillations per second
What is the equation for freaquency of a wave
F= 1/T
How do you work out wave speed
Wavespeed= Frequency x Wavelength
What is wave speed measured in
m/s
Meters/ second
What are transversal waves
Oscillations are perpendicular to the direction of engery transfer
(wave goes up and down)
What are examples of transverse waves
- Electromagnetic spectrum
- Water waves
- Guitar strings
What type of waves are light waves
Transversal
What are longitudinal waves
Oscillations are parrallel to the direction of engery
(Spread out and compressed bits)
What type of waves are sound waves
Longitudinal
What are some examples of longitudinal waves
- Sound waves
- Some shock waves
What 3 things can happen when a wave meets a boundry between materials
- Absourbed (engery taken in)
- Reflected (bounced off)
- Transmitted (goes through)
What are diagrams of waves called
Ray diagrams
What is the main rule in reflection
Angle of incidence = Angle of reflection
How is the normal line drawn in a Ray diagram
- Dashed
- Perpendicular to the boundry (90 degrees)
What is the normal line used for
To measure the angle of incidence
What is the ‘point of incidence’
The place where the incoming ray touches the boundry
What is specular reflection
When the boundry is flat so all of the normal lines are parallel so all of the light rays are reflected in the same direction
What type of image does specular reflection produce
A clear image (like you see in a mirror)
What is diffuse/ scattered reflection
When the boundry is bumpy so the normal lines are not parallel which means that the light rays are reflected in different directions
What type of image does diffuse reflection prouduce
A matte surface- you cannot see a reflection clearly
What happens to the speed of a wave when it enters a different material
It can change speed
Why do waves change speed when they move into different materials
Because the materials have different densities
How does density effect a light wave
Denser materials = Slower wavespeed
