Waves Flashcards
What is an example of transverse waves?
The ripples on a water surface.
What is an example of longitudinal waves?
Sound waves travelling through air.
What do all waves transfer?
All waves transfer energy from one place to another.
What is the keyword describing waves moving up and down?
Oscillations.
What are transverse waves?
In transverse waves the oscillations are perpendicular to the direction of the energy transfer.
What are compressions?
Regions where the particles are close together in longitudinal waves.
What are rarefactions?
Regions where the particles are spaced out in longitudinal waves.
What are longitudinal waves?
Ina longitudinal wave, the oscillations are parallel to the direction of the energy transfer.
What do all longitudinal waves require to travel in?
A medium. e.g air, a liquid, a solid
**TRUE OR FALSE?
**
All transverse waves require a medium to travel in.
FALSE.
Not all transverse waves require a medium.
For both ripples on a water surface and sound waves in air, is it the wave or water/air molecules that travel?
For both ripples on a water surface and sound waves in air, it is the wave and not the water or air itself that travels.
What is the amplitude?
The amplitude is the furthest point away the wave vibrates from this undisturbed position.
What is the wavelength?
The wavelength of a wave is the distance from a point on one wave to the equivalent point on the adjacent wave.
What is frequency?
The number of waves passing a point in a second
Frequency is given the symbol f and is measured in Hertz (Hz)
How much does 1Hz equal?
1 Hz = 1s
What is the period?
The period is the time (in seconds) for one wave to pass a point.
What is the formula for period?
period (s) = 1/frequency (Hz)
What is the wave speed?
The wave speed is the speed at which the wave moves through the medium (ie the speed at which energy is transferred)
What is the formula for wave speed?
v (wave speed (m/s)) = f (frequency (Hz)) × λ (Wavelength (M))
Describe a method to measure the speed of sound waves in air.
- Have 2 people separated at a distance of 500 metres.
- Person A is holding a pair of cymbals and Person B is holding a timer.
- Person B starts the timer when they see person A clash the cymbals together.
- Person B stops the timer when they hear the sound of cymbals of crashing
- We then calculate the speed of the sound waves travelling by diving the distance travelled by the time taken
What problems are their with the method to measure the speed of sound waves in air?
-Every person has a different reaction time.
- The time between seeing the cymbals clash and hear the sound is short indeed
What is the method to set up Required Practical 8: Ripple Tank?
- Set up the apparatus: Set up the ripple tank, in the water is a vibrating bar which is connected to a power pack. Above the ripple tank is a lamp and under the tank is a sheet of white paper. When light shines through the water, it produces the images of waves on paper.
- We now use this set-up to measure the wavelength, frequency and speed of the water waves. Easiest way to do this is by recording the waves on your phone allowing us the play back the the recording at different speeds or freeze the image.
How do we measure wavelength Required Practical 8: Ripple Tank?
- To measure we place a ruler on the paper.
- We then freeze the images of the waves.
- We now measure the distance between one wave and ten waves further
