P6 - Waves Flashcards
What can waves be?
Transverse or longitudinal
Example of a transverse wave
The ripples on a water surface - it is the wave that travels and not the water
What do longitudinal waves show
Compression and rarefaction
Examples of a longitudinal wave
Sound waves travelling through air - it is the wave that travels and not the air itself
What is the difference between transverse and longitudinal waves (3)
- In transverse waves the oscillations (vibrations) are perpendicular (at 90°) to the direction of energy
- Where as in longitudinal waves, the oscillations are parallel to the direction of energy transfer
What is the amplitude of a wave
Is the maximum displacement of a point on a wave away from its undisturbed position
What is the wavelength of a wave
Is the distance from a point on one wave to the equivalent point on the adjacent wave
What is the frequency of a wave
Is the number of waves passing a point each second
Equation for period
Period(s) = 1/frequency (Hz)
Equation for frequency
Frequency = 1/period (s)
What is wave speed
Is the speed at which the energy is transferred (or the wave moves) through the medium
The wave equation that all waves obey
Wave speed (m/s) = frequency (Hz) x wavelength (m)
Wave diagram
Check photos
Describe a method to measure the speed of sound waves (3)
- set up an oscilloscope so the detected waves at each microphone are shown as separate waves
- start with both mics next to the speaker, then slowly move away until the two waves are aligned on the display, but have moved exactly one wavelength apart
- Measure wavelength - then use the wave speed formula
Measure the frequency, wavelength and speed of waves in a ripple tank - required practical (apparatus) (5)
- Lamp
- Dipper
- Water
- Signal generator
- Metre ruler
Measure the frequency, wavelength and speed of waves in a ripple tank - required practical (method) (4)
- Using a signal generator attached to the dipper of a ripple tank you an create water waves at a set frequency
- Dim the lights and turn on lamp - should see wave crests as shadows on the screen below
- The distance between each line is the wavelength - find the average wavelength after 10 lines
- Use the equation wave speed = wavelength x frequency
Measure the frequency, wavelength and speed of waves in a solid - required practical (apparatus) (6)
- Vibration transducer
- String
- Pulley
- Signal generator
- Bench
- Masses