P5 Flashcards
What is a wave?
Something that transfers energy without transferring matter.
Imaging particles vibrating to push the other but the returning to their original position
How do sound waves travel in the different states of matter?
Least in gas, highest in solids
This is because the particles are closer together
What is transverse wave?
A wave in which the vibrations are perpendicular to the direction of energy transfer.
Eg: light waves /EM waves
What is a longitudinal wave
Waves in which vibrations are parallel to the direction of energy transfer
Eg: sound waves
What should you imagine when looking at wave diagrams
That the wave is moving from left to right- even though draw as stationary
What is the normal line?
The mean position of a particle, about which it vibrates and oscillates
What is amplitude?
The maximum displacement of particles from their mean position.
Normal line to trough.
The more amplitude = more energy
What is the wavelength?
The distance from one peak to another peak
What is frequency?
The number of peaks passing a point every second.
Inversely proportional to wavelength
Eg large frequent, small wavelength
What are compressions?
Particles squashed together
High pressure
PEAKs
What are rarefactions?
Particles spread far apart
Low pressure
Troughs
What is the formula for wave speed?
Wave speed = frequency ✖️wavelength
C= f ✖️į (iambs)
Wave speed =m/s
Frequency =hertz (Hz)
Wavelength = m
What is the time period?
The time taken to produce 1 wave,
The equation is 1/ frequency = TP
1/TP= frequency
What is the only variable that can change the velocity of a wave?
The medium it is travelling , not the energy transferred
What does amplitude correspond to in sound?
The larger the amplitude, the larger the volume
What does frequency correspond to in sound?
The pitch,
The higher the frequency , the higher the pitch
What is the difference between longitudinal and transverse waves?
Transverse = oscillations are perpendicular
Longitudinal = oscillations are perpendicular
to the direction of energy transfer
Can an electro magnet travel in a vacuum?
Yes, does not require particles to travel
Describe electromagnet radiation:
A transverse wave that is a Light wave. Does not need particles to travel. The frequency/wavelength determines the colour of the light
How are electro magnetic waves created?
Vibrating charged particles
What is the difference between sound waves and EM waves?
Sound = vibrating particles
Transfer kinetic energy
EM= vibrating charged particles
Transfer electromagnet energy
List the EM spectrum in terms of increasing frequency:
〰️radio waves
〰️microwaves
〰️infrared waves
〰️visible light
〰️Ultra Violet waves
〰️X rays
〰️gamma ray
What must be noted about the frequency and wavelength of the EM spectrum ?
Increasing frequency = increasing energy
Increasing energy = smaller wavelength
How is the light intensity measured?
The amplitude of the EM radiation
What is the light intensity
The given light in a given time over a given area
What is the speed of light?
3 ✖️10^8
All EM waves travel at this speed
How are sound waves produced?
vibrating particles,
colliding with neighbouring particles,
transferring energy
Describe (visible) light waves
- Pass through air & glass but not other solids
- The see /cameras
Describe infra red waves:
1, pass through air, glass but are stopped by solids
2. night vision,toasters
3. Energy is absorbed by skin allowing it to heat up
Describe microwaves :
- Easily pass through the Earth’s atmosphere and air
- Used to cook food
- Heats up water particles
Describe Radio waves:
- Pass through air and solids
2.Radio and Tv signals
Describe Ultraviolet waves
- Can moderately penetrate Earth’s atmosphere but not skin
- Produces vitamin D
- A little ionising could possibly cause cancer
Describe X rays
- Penetrates skin and thin metal however is stopped by bone and dense metals
- Used for X-ray imaging
- Lightly ionising and can give rise to cancer
Describe Gamma rays
- Very penetrating !Stopped by thick lead materials
- Treatment of cancer
- Quiet ionising and can cause cancer
What two variables can you calculate from this graph?
What two variables can you calculate from this graph ?
how are electromagnetic waves produced?
vibrating charged particles,
oscillating electrostatic field,
moving magnetic filed
transfers electro magnetic energy