P6 Flashcards
What happens when waves travel through a medium?
The particles of the medium oscillate and transfer energy between each other. But overall the particles stay in the same place , only energy is transferred
What is the amplitude of a wave?
Maximum displacement of a point on the wave from its undisturbed position
What is the wavelength of a wave?
Distance between the same point on two adjacent waves(e.g between the trough of one wave and the trough of another)
What is the frequency of waves?
Number of complete waves passing a certain point per second . Frequency is measured in hertz (hz)
What can you find with the frequency?
The period of a wave using the equation :
Period = 1/ frequency
This is the amount of time it takes for a full cycle of the wave.
What are transverse waves?
Oscillations are perpendicular to the direction of the energy transfer. Most waves are transverse , including:
- all electromagnetic waves, eg light
- ripples and waves in water
- wave on a string
What are oscillations?
Vibrations
What are longitudinal waves?
Oscillations are parallel to the direction of energy transfer. An example is w
What are compressions and rare fractions in longitudinal waves?
Compressions is when the wave tightens up and rare fractions is when the wave loosens
What is the wave speed
Speed at which the energy is transferred through the medium
How to calculate wave speed?
Wave speed = frequency x wavelength
How to measure the speed of sound?
Use oscillopes. By attaching a signal genartor to a speaker you can generate sounds with specific frequency. You can use two microphones and an oscillope to find the wavelength of sound waves generated.
Process of measuring speed of sound?
1) Set up oscillope so detected waves at each microphone are shown as separate waves.
2) both microphones next to speaker , then slowly move one away until the two waves are aligned
3) measure distance between the microphones to find one wavelength. Use wavelength formula to calculate speed of sound 330 m/s
What 3 things can happens when a wave meets a boundary between two materials?
1) wave is ABSORBED by second material-wave transfers energy to the materials energy stores. Often , the energy is transferred to a thermal energy store which leads to heating
2) wave is TRANSMITTED through second material-wave carries on travelling through new material. This often leads to refraction. This can be used in communications as well as in the lenses of glasses and cameras
3) wave is REFLECTED -incoming ray is neither absorbed or transmitted , but instead sent back away from the second material
What type of wave is electromagnetic waves?
Transverse waves that transfer energy from the source of the waves to the absorber
