P6 Waves Flashcards by Ciara Brady

What are the two types of waves?

Transverse
Longitudinal

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What is a transverse wave?

A wave for which the oscillations are perpendicular to the direction of energy transfer

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What is a longitudinal wave?

A wave for which the oscillations are parallel to the direction of energy transfer

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Give two examples of transverse waves

Electromagnetic waves
Seismic waves
(Water)

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Give two examples of longitudinal waves

Sound waves
Seismic p-waves

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What are the two parts of a longitudinal wave called?

Compressions and rarefactions

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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

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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

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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

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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

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What is the equation for speed

Speed = frequency x wavelength

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What is the equation for a period of a wave?

T= 1/f

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What is the amplitude of a wave?

Height of a wave

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What is the wavelength of a wave?

Distance between two peaks

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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

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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

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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