3.1 Progressive Waves Flashcards
What are progressive waves?
Moving waves
What do waves do?
Carry energy from one place to another without transferring any material
What are waves caused by?
Something making particles or fields oscillate at a source
These oscillations pass through the medium as the wave travels, carrying energy with it
A wave transfers this energy away from its source, so the source of the wave looses energy
How can you tell that waves carry energy?
- EM waves cause things to heat up
- X-rays and gamma rays knock electrons out of their orbits
- loud sounds cause large oscillations of air particles which can make things vibrate
- wave power can be used to generate electricity
What three things can happen to waves as they travel?
- Reflection
- Refraction
- Diffraction
What happens when a wave is reflected?
The wave is bounced back when it hits a boundary
What happens when a wave is refracted?
The wave changes direction as it enters a different medium. The change in direction is a result of the wave slowing down or speeding up
What happens when a wave is diffracted?
The wave spreads out as it passes through a gap or around an obstacle
What is displacement in regards to waves?
How far a point on the wave has moved from its undisturbed position
What is the symbol for displacement and what is it measured in? (Waves)
Symbol: x
Measured in: metres
What is amplitude in regards to waves?
The maximum magnitude of the displacement (e.g. the distance from the undisturbed position to the crest/trough)
What is the symbol for amplitude and what is it measured in?
Symbol: A
Measured in: metres
What is wavelength?
The length of one whole wave oscillation or wave cycle (the distance between two crests of a wave)
What is the symbol for wavelength and what is it measured in?
Symbol: lambda
Measured in: metres
What is the period in regards to waves?
The time taken for one whole wave cycle
What is the symbol for period and what is it measured in?
Symbol: T
Measured in: seconds
What is frequency in regards to waves?
The number of whole wave cycles per second passing a given point (or the number of whole wave cycles given out from a source per second)
What is the symbol for frequency and what is it measured in?
Symbol: f
Measured in: hertz
What is phase in regards to waves?
A measurement of the position of a certain point along the wave cycle
What is phase difference in regards to waves?
The amount by which one wave lags behind another wave
What can phase and phase difference be measured in?
- degrees
- radians
- fractions of a cycle
How are frequency and period linked?
Frequency = 1/period
