Topic 6 - Waves Flashcards
What are the two types of waves?
Transverse or longitudinal
Given example of a transverse wave
The ripples on the water surface
Give an example of a longitudinal wave
Sound waves travelling through air
What do longitudinal waves show?
Areas of compression and rarefraction
Describe transverse waves
The oscillations are perpendicular to the direction of energy transfer
What directions do transverse waves vibrate in?
Up-and-down
How does a transverse wave move?
Up-and-down
Describe longitudinal waves
The oscillations are parallel to the direction of energy transfer
How does a longitudinal wave move?
Left and right
Give an example using a guitar string to show that the wave moves?
If you strum a guitar string and create sound waves, the sound waves don’t carry the air away from the guitar and create a vacuum
Give an example using ripples in the water to show that waves move
If you drop a twig into a calm pool of water, ripples fall on the water surface, the ripples don’t carry the water away with them
What is amplitude?
The maximum displacement of a point on the wave away from its undisturbed position
What is wavelength?
The distance from a point on one wave to the equivalent point on the adjacent wave
What is frequency?
The number of waves passing through a point each second
What is the equation to calculate a period?
Period (secondsw) = 1/frequency (hertz)
What is wave speed?
The speed at which the energy is transferred (or the wave moves) through the medium
What is the wave equation?
Wave speed (m/s) = frequency (hertz) x wavelength (m)
What are the three ways that you can measure the speed of a wave?
- using oscilloscope to measure the speed of sound
- Measure the speed of water ripples using a strobe light
- use the wave equation for waves on strings
When are waves reflected?
At the boundary between two different materials
When can waves be absorbed or transmitted?
At the boundary between two different materials
What are the three things that can happen to waves at the boundary between two different materials?
Reflection, absorption and transmission
What is the equation for the angle of incidence and reflection?
Angle of incidence = angle of reflection
What happens when a wave is absorbed?
Energy is transferred to the materials energy stores
What happens when waves are transmitted?
They carry on travelling through the new material which often leads to refraction