P6 Waves Flashcards
What are the two types of waves?
Transverse
Longitudinal
What is a transverse wave?
A wave for which the oscillations are perpendicular to the direction of energy transfer
What is a longitudinal wave?
A wave for which the oscillations are parallel to the direction of energy transfer
Give two examples of transverse waves
Electromagnetic waves
Seismic waves
(Water)
Give two examples of longitudinal waves
Sound waves
Seismic p-waves
What are the two parts of a longitudinal wave called?
Compressions and rarefactions
What are the similarities between transverse and longitudinal waves?
Both transfer energy
Both can be reflected (like light waves do off a mirror)
Both have repeated cycles
What are the differences between transverse and longitudinal waves?
How the particles oscillate
Transverse waves have peaks and troughs whereas longitudinal waves have compressions and rarefactions
Longitudinal waves always need a medium (matter) to transfer through
Define frequency
The number of waves passing a point in 1 second
It is measured in hertz (Hz)
The longer the wavelength the lower the frequency
Define period
Period is how long it will take for only one wave to pass a point.
Measured in seconds, it is the inverse of frequency
What is the equation for speed
Speed = frequency x wavelength
What is the equation for a period of a wave?
T= 1/f
What is the amplitude of a wave?
Height of a wave
What is the wavelength of a wave?
Distance between two peaks
What is a experiment to find wavelength?
Place a metre ruler at the side of the screen perpendicular to the wave fronts
Use the metre ruler to measure the length of the screen
Take the photograph of the shadow on the screen
Count the number of complete waves on the screen
Determine the wavelength by dividing the number of complete waves
What is an experiment to find frequency?
Count the number of waves that pass a given point
Time how long it takes for the waves to pass that point using a stop clock
Frequency is the number of waves divided by the time taken
What are some examples of electromagnetic waves?
Radio waves
Microwaves
Gamma rays
Infra red
Visible light
X-rays
Ultra violet
What are the uses of radio waves?
Mainly used for communication
Where are radio waves on the electromagnetic spectrum?
At the end so it has
Long wavelength
Low frequency
What are the dangers of radio waves?
Large doses are believed to cause cancer, leukaemia and other disorders
What are the uses of microwaves?
Microwaves
Mobile phones
Wi-Fi
Speed cameras
Radar
What are the uses of gamma rays?
Kill cancer cells,
Radiotherapy (targeted)
Tracers,
Sterilise food, +
Medical equipment
What are the uses of infra red?
Remote controls
Heal sports injuries
Night sights
Weather forecaster
Rescue workers
Thermal imaging
Police helicopters
Alarm systems
What are the uses of visible light?
Compact disk and DVD player
Laser printers
Weapon aiming systems
To see
What are the uses of ultra violet?
Sun tan
Detecting forged bank notes
Kill microbes
Sterilise
Body produce vitamin D
What are the uses of X-rays?
See inside people
Airport security
Used by astronomers
What are the dangers of microwaves?
Cataracts
What are the dangers of gamma rays?
Cell damage
Mutations
What are the dangers of infra red?
Overheating
What are the dangers of visible light?
Damage the retina in your eye
What are the dangers of X-rays?
Cell damage
Cancer
What is the order of the electromagnetic spectrum?
Long wavelength, low frequency
Radio waves
Microwaves
Infra red
Visible light
Ultra violet
X-rays
Gamma rays
Short wavelength, high frequency
Rock Music Is Very Useful for eXperiments with Goats
What do waves transfer, and what do they not transfer?
Waves transfer energy but do not transfer matter
What happens when waves are reflected
Speed and wavelength does not change
Refraction
Waves cross a boundary between different mediums causing a change in speed, direction and therefore:
Wavelength = frequency
Refraction (glass and air)
Waves travel slower in glass
The edge of the waves that reach the boundary first slow down first
The waves in air continue at a faster speed
This causes the wave to change direction
Reflection
Angle of incidence = angle of reflection
Refraction through a glass block
Wave slows down and bends towards the normal line due to entering a more dense medium
Wave speeds up and bends away from the normal line due to entering a less dense medium
Wave slows down and is not bent, due to entering along the normal line
Refraction through a glass block (method)
Place a metre ruler perpendicular to the side of the screen and measure the length of the side of the screen
Take a photograph of the shadow on the screen
Count the number of waves in the photograph. Determine the wave length by dividing length of screen by the number of complete waves
Count the number of waves that pass a given point
Time how long it takes for
Different surfaces of a Leslie cube
A shiny metallic surface
A white surface
A shiny black surface
A matt black surface
Method of Leslie cube
Fill the Leslie cube with hot water
Then point a
