Ch - 14 (Properties of waves) Flashcards
What do waves transfer?
- Energy and information
- Oscillations or vibration
what is the difference between the particles (or oscillations), and the wave itself?
- Motion of the wave causes particles to move
- particles themselves are not the wave.
How is vibration in ropes?
Wave travel perpendicular to vibration of rope.
How is the vibration in springs?
Wave travel parallel to vibration of coils.
Define crest
The highest point of the wave above the equilibrium, or rest position.
Define trough
The lowest point of the wave below the equilibrium or rest, position.
Define amplitude
Maximum displacement of molecules away from mean position
Define wavelength
Distance between two successive crests or troughs (or compressions and rarefaction)
How is the wavelength measured in a transverse wave?
One peak to the next peak
How is the wavelength measured in a longitudinal wave?
Center of one compression to the center of another compression.
Define frequency
Numbers of oscillations per unit time (per sec)
Define wave speed
Distance travelled by wave each second.
what is the formula of wave speed?
Wave speed = frequency x wavelength
Define wavefronts
useful way of picturing waves from above.
How are wavefronts visualised?
From above
What are the two types of waves?
- Transverse
- Longitudinal
Define transverse waves.
waves where the point along the length vibrates at 90 degree to the direction of energy transfer.
How is a transverse wave?
- energy transfer in same direction as wave motion.
- transfer energy but not the particle.
- move in solids, on surface of liquids, but not inside liquid or gases.
- EM waves move in solids, liquids and gases.
What are examples of transverse waves?
- Ripple waves
- S seismic waves
- EM waves
- vibrations
Define longitudinal waves.
waves where the point s along its length vibrate parallel to the direction of energy transfer.
How is a longitudinal wave?
- energy transfer is in same direction as wave motion.
- transfer energy but not the particles of the medium
- can move in all states
- cannot move in vacuum
What are the key features of a longitudinal wave?
- Compressions (close together)
- Rarefactions (further apart)
What’s re examples of longitudinal waves?
- Sound waves
- P waves
- pressure waves
Compare the structure of transverse and longitudinal waves?
Transverse: Peaks and troughs
Longitudinal: Compression and rarefactions
Compare the vibration of transverse and longitudinal waves?
Transverse: 90 degree
Longitudinal: Parallel
Compare the vacuum of transverse and longitudinal waves?
Transverse: EM waves only
Longitudinal: NA
Compare the material of transverse and longitudinal waves?
Transverse: Can move in states
Longitudinal: Can move in states
Compare the density of transverse and longitudinal waves?
Transverse: Constant density
Longitudinal: Changes in density
Compare the pressure of transverse and longitudinal waves?
Transverse: Pressure is constant
Longitudinal: Changes in pressure
Compare the speed of wave of transverse and longitudinal waves?
Transverse: Dependent
Longitudinal: Dependent
Define reflection.
a wave hits the boundary between 2 media and does not pass through but stays in original medium.
What is the law of reflection?
angle of incidence = angle of reflection
Define refraction
a waves passes a boundary between 2 different transparent media and undergoes a change in direction.
What are the two effects of refraction?
- wavelength can increase or decrease
- waves can change directions.
What happens to the wavelength when a wave is diffracted?
Wavelength remains constant
What are the factors affecting diffraction?
The gap between to points
Define period.
Time taken for one complete oscillation
