Waves Flashcards
Amplitude
Maximum displacement from the centre
Wavelength
Distance between on point on a wave to the same point on the next wave.
Transverse Wave…
- Oscilates perpendicular to the energy transfer
- Doesn’t require medium for travel
- E.g Light or EM waves
Longitudinal Waves…
- Oscilate parrallel to energy transfer
- Reqires medium to travel through
- E.g sound or seismic (vibrations) waves
wave speed equation
wave speed = frequency X wavelength
wave speed = 1/time period X wavelength
what are the units for wave speed, Frequency and Wavelength?
WS = meters per second (m/s) F = Hertz (Hz) WL = Lamda (λ)
Frequncy equation
Frequency = 1/time period
Frequency = wave speed/ wavelength
the speed of light and EM waves in a vaccum is always equal to…
3 X 10^8 m/s
The EM spectrum from highest frequency to lowest.
- Gamma Rays
- X-Rays
- Ultra-Voilet
- Visible Light
- Infared
- Microwaves
- Radio Waves
what does the PIE symbole represent?
π = Radian
JUST THE SYMBOL, NOT ACTUALLY PIE!!!!!!!!
Phase difference
When two waves have the same frequency and wavelength PD tells us the difference in phase angle between the waves.
AntiPhase
if two waves are in antiphase they will have a phase difference of 180degrees.
This means the peaks will over lap with the troughs.
cheese
cheese
Coherent Waves
Waves that have a constant pahse difference with one another.
Can only be coherent with same wavelength and frequency.
Coherent waves can interfere constructively and destructively.
path difference
difference in distance travelled by two waves from their sources to a given point.
Constructive interference…
Will take place when the peaks of one wave line up with the peaks of the other wave.
Will take place if path difference is equal to nλ
Destructive interference…
Will take place when the peaks of one wave line up with the troughs of the other wave.
Will take place if the path difference is equal to n/2 λ
Diffraction
Changes the direction of a wave and causes it to spread
occurs when a wave:
passes an edge
passes through a narrow gap
goes past an object
Does diffraction change the properties of waves?
None of the properties of a wave are changed by diffraction!!!!!!
The wavelength, frequency, period and speed are the same before and after diffraction.
The only change is the direction in which the wave is travelling.
Superposition
When two waves interfere, the amplitude of the resultant wave is found by adding the amplitudes of the two individual waves
This is known as superposition
can result in constructive or destructive interference
Double slit
When a wave passes through two gaps and diffracts, this is known as double slit diffraction
Single slit diffraction is a wave passing through one gap.
This results in wave interference both constructive and destructive.
Diffraction grating
A large number of evenly spaced parallel slits.
What is white light made of?
Made up of all colours on the rainbow
Red has the longest wavelength
Violet has the highest frequency
Refraction
When a wave moves through a medium and changes speed/direction
Electrons will _____ radiation of a given frequency to go up an energy level
Electrons will absorb radiation of a given frequency to go up an energy level
Electrons will ______ radiation of a given frequency to go down an energy level
Electrons will emit radiation of a given frequency to go down an energy level
