Waves Flashcards
What are the two types of wave
longitudinal, transverse
What is the amplitude of a wave
height of the wave measured from the centre of the wave.
this is a measure of the energy carried by the wave
What is the wavelength
this is the distance between two corresponding points on the wave and it measured in metres
WHat is the symbol for wavelength
lambda λ
What is the frequency
this is how many waves pass by every second
What is frequency measured in
Hertz (Hz)
What is the time period
this is the time it takes for one wave to complete its cycle(s)
What does a high frequency mean in terms of time period
short time period
What does a low frequency mean in terms of time period
longer time period
what is the equation for time period of a wave
T = 1/f
What is the equation for frequency of a wave
f = 1/T
What is a transverse wave
A wave that oscillates particles perpendicular to the motion of the wave
What is a longitudinal wave
Particles vibrate in the same direction as the motion of the wave
WHat is the length of a wave either from peak to peak or trough to trough
wavelength
What is the equation for wave speed
frequency x wavelength (v= fλ)
WHat is wave speed measured in
m/s
What is the law of reflection
The angle of incidence, i equals the angle of reflection, r
Name 2 longitudinal waves
-sound waves
-seismic waves
-ultrasound waves
Name 3 transverse waves
-All EM waves
-Water waves
-Wave on a string
What do you use an oscilloscope for
measuring the speed of a wave
How do you use an oscilloscope
-Set up oscilloscope so the detected waves at each microphone are shown as separate waves
-Start with both microscopes next to the speaker, then move one away until the two waves are aligned on the the display but have moved exactly one wavelength apart
-Measure the distance between the microphones to find one wavelength
-Use V=fλ to find the speed (v) of the sound waves passing through the air- the frequency is whatever you set the signal generator to.
-The speed of sound in air is around 330m/s so check your results agree with this
How to measure the speed of water ripples using a lamp
-use signal generator attached to dipper of a ripple tank; use to create waves at a set frequency
-use a lamp to see wave crests on a screen below the tank, make sure size of shadows equal size of waves
-distance between each shadow line is equal to one wavelength. Measure the distance between the shadow line is equal to one wavelength.
-Measure the distance between shadow lines 10 wavelengths apart, divide this by 10 to find average.
-use v=fλ to find speed
-suitable for investigating waves because you can measure wavelength without disturbing the wavelength
WHy are wave tanks useful for investigating waves
You can measure the wavelength without disturbing the waves
True or false. All waves can be absorbed, transmitted, or reflected
True
What is a specular reflection
When a wave is reflected in a single direction by a smooth surface
e.g. light reflected by a mirror
What is a diffuse reflection
When a wave is reflected by a rough surface and the reflected rays are scattered in lots of different directions
e.g. piece of paper
What does a surface look like when light is reflected by a rough surface and you don’t get a clear reflection of objects
matte
