Flashcards in Waves Deck (12):
A wave can be described as a disturbance that travels through a medium from one location to another location.
What do waves do ?
Energy is transferred from one place to another without causing any net movement of material .
An example of wave ?
Your in the water you move up and down because you are supplied with energy
The water doesn't move but the waves move which causes vibration so therefore its transfers energy without transferring matter .The oscillation of the wave moves not the water.
If the water moved your are moving as well . But in this case the water isn't the oscillations and the vibration of the wave caused you to move up and down .
Oscillation go up and down or side to side.
Direction of wave propagation( way it moves) is perpendicular to direction of oscillation (vibration)
Examples include :
Waves on a string
Direction of wave propagation is perpendicular to oscillations .
Oscillations go side to side as well as the wave energy.
Examples include :
Direction of wave propagation is parallel to the direction of oscillation .
Compression and Rarefaction occur in sound waves rarefaction is far apart and compression is packed particles which are close to each other .
What is sound waves an example of and how do they produce sound ?
Sound waves are an example of longitudinal waves .Such as when the speaker produces sound the particles are pushed in the air rather than to your ear .Come in the form of compression or rarefaction in the air
Particles also move in the direction of parallel to the direction
Are transverse waves because waves are perpendicular to each other and also to the direction of propagation .
They also can be polarised .
In three dimensions so some can be polarised in one plane and some in another plane at 90 degrees to the first one .It will also remove all the components that have oscillations in the plane at 90 degrees.
Why do polarising sunglasses work ?
They work because when sunlight is passed through a polarising filter half of the sunlight intensity is removed .As light has been reflected tends to be mostly polarised in one plane only . Polarising glasses are good for cutting out glare from reflective surfaces
Explain why there cannot be an equivalent to this for sound waves ?
Because they are longitudinal waves meaning the direction of propagation is the same as the direction of oscillation . Therefore enegy travels in one direction not many .
Whereas transverse waves travel in many directions and have oscillations in the plane of 90 degrees.
Why are sound longitudinal waves ?
Because the direction of propagrtion and direction of oscillation are the same .Aswell as when sound waves travel in the air as particles create compression and rarefraction .
What evidence can you give for classrifying radio or tv sigals as transverse waves ?
Because the dectectors for transvese waves must be aligned at right angles to the direction of propagration to receive a good signal .For radio when you move the aerial around the signals come and go .