Waves Flashcards
What is a transverse wave?
- Oscillations perpendicular to direction of travel
- Don’t require a medium (usually!)
- All EM waves are transverse
What is a longitudinal wave?
- Oscillations parallel to direction of travel
- Compressions and rarefactions happen
- Require a medium
What type of wave are mechanical waves?
They can be transverse or longitudinal. However, they require a medium.
The bigger the amplitude of the waves…
… The more energy they carry
What is frequency?
The number of waves passing a point per second.
What is the unit for frequency?
Hertz (Hz)
How many waves per second equal 1Hz?
1 wave per second = 1 Hz
What is the equation for wave speed?
v = f x lambda
Speed = Frequency x Wavelength
The angle of incidence…
…Is equal to the angle of reflection.
What is refraction?
The change in direction of a wave when it hits a boundary.
When does refraction not happen?
When the waves hit the boundary at 90*
Which way do waves bend when entering a medium that slows them down?
Toward the normal.
What happens to water waves when they enter shallower water?
They slow down (and bend towards the normal)
What is diffraction?
The spreading of waves when they pass through a gap or move past an obstacle.
When is diffraction most noticeable?
When the width of the gap is similar to the wavelength.
Why can hills be a problem when receiving TV reception?
The waves cannot diffract enough to reach certain places in hilly areas.
What is interference?
The reinforcing or cancelling out of any type of wave when two identical sets of waves overlap.
What happens when a crest meets a trough?
They cancel each other out.
What happens when a trough meets a trough or a crest meets a crest?
They reinforce each other.
