P6 Waves Flashcards
What’s the two types of waves
Transverse and longitudinal 
What do waves do
Transfer energy from one place to another
What a transverse waves
Waves with oscillations perpendicular to the direction of energy transfer
What are longitudinal waves
Where the oscillations are parallel to the direction of energy transfer and require a median to travel through 
What is meant by the term amplitude
The maximum displacement of a point on the wave from its undisturbed position
What is meant by the term wavelength
The distance from a point on one wave to the equivalent point on the adjacent wave
What is frequency
The number of waves passing a point each second
What is 1 Hz equivalent to
One wave per second
What is meant by the term period
The time taken for one wave to pass a point
What is wave speed
The speed at which the wave moves through a medium
What is the first step to measure the speed of sound waves in air
Person B starts timing when they see person A clashes the cymbals together
What is step two in measuring the speed of sound waves in air
Person B stops timing when they hear the sound of the cymbals clashing
What is step three in measuring the speed of sound waves in air
Calculate the speed of sound waves by dividing the distance travelled by the time taken
How can the accuracy of an experiment be improved
By completing multiple readings to create a mean result and by removing anomalous results
What causes a microphone to vibrate (S)
The particles hitting the cone
How does sound travel through the human ear (s)
The sound waves funnel through the air where they hit the eardrum which is a thin membrane. The sound waves cause the eardrum and other parts to vibrate which causes the sensation of sound
What’s the condition that allows soundwaves in the air to trigger vibrations in solids (s)
Through the limited range of frequencies which is around 20 Hz to 20,000 Hz for humans
What happens when waves change medium (s)
The speed can change
Does the frequency change when the medium changes (s)
No
What instrument allows soundwaves to be viewed (s)
A cathode ray oscilloscope 
What is the pitch at a high frequency (s)
High pitch 
At a low frequency what is the pitch (s)
Low pitch
What does a small amplitude produce (s)
A quiet sound
What does a large amplitude produce (s)
Loud sound
Why can Longitudinal waves only move through a medium
Because longitudinal waves move by particles vibrating
Why can sound waves not pass through a vacuum
There are no particles
Can soundwaves be reflected
Yes
What happens if a wave is transmitted through an object
The wave passes straight through
What happens if a wave is absorbed
The energy of a wave is absorbed so the amplitude decreases
What can happen to a wave when it hits a Boundry
It can be absorbed transmitted reflected or refracted
What is the angle of reflection equal to
The angle of incidence 
What are ultrasound waves
Waves with a higher frequency than the upper limit of human hearing
What is the frequency of an ultrasound wave
At least 20,000 Hz
What happens when an ultrasound wave meets the boundary between two different densities
It partially reflects
What can ultrasound waves be used for in the medical industry
To produce images of internal organs and foetuses
What is the advantages of using ultrasound over radiation
Ultrasound does not cause mutations or increase the risk of cancer
What can ultrasound be useful in welding
It can detect hidden defects or problems with a weld 
How do earthquakes occur
Through a sudden movement between the tectonic plates in the earths crust
What do earthquakes cause
Seismic waves which carry energy
When the seismic waves pass through the Earth what can they be detected by
Seismometers
What do the readings of a seismometer reveal
The interior of the Earth
What are the two types of seismic waves
P-waves and S-waves
What are P-waves
Longitudinal waves
What can longitudinal waves only pass through 
Solids and liquids
Which type of seismic waves is faster
P waves
What type of waves are S waves
Transverse waves
What can transverse waves only pass through
Solids
Why do seismic waves travel in curved paths
Because the density changes in the Earth
What are S-wave shadow zones
Regions where S waves don’t pass through 
Why can S waves not pass through the outer core
Because S waves cannot pass through a liquid
What does the S-wave shadow zone tell scientists
The Earth must contain a liquid core
Why do P-waves shadow zones occur
P-waves travel faster in solids than in liquids
Why do P-waves refract
Because the P-waves slow down as they enter the liquid outer core
What are electromagnetic waves
Transverse waves that transfer energy from the source of the waves to an absorber
State the electromagnetic spectrum from lowest frequency to highest frequency
Radio wave, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays
What part of the electromagnetic spectrum can be detected by the human eye
Visible light
What speed do all electromagnetic waves travel through in a vacuum 
3x10^8
What affects whether a material absorbs transmits or reflects electromagnetic waves
The wavelength
What happens when electromagnetic Waves are generated or absorbed
Changes take place in atoms or in the nuclei of atoms
What happens when atoms are heated
Electrons move from one energy level to a higher one
After an atom is heated and returned to the original level what does it release
An electromagnetic wave
Which three electromagnetic waves are potentially hazardous
Ultraviolet, x-rays and gamma rays
Why is ultra violet potentially hazardous
It increases the risk of skin cancer and can cause premature aging of the skin
Why are x-rays and gamma rays potentially hazardous
They are ionising radiation which can cause mutation of genes which increases the risk of cancer
What does damage caused by radiation depend on
The type and dose of radiation
How can radio waves be produced
When electrons oscillate in electrical circuits
What happens when radio waves are absorbed
Electrons in the circuit oscillatewhich causes an alternative current
What can radio waves be used for
To transmit radio and terrestrial TV signals
Why are radio waves used to transmit radio
Because they can travel long distances before being absorbed
What are microwaves used for
To heat food
Communicate with satellite in space
Why are microwaves used to heat food
Water molecules absorb the energy of microwaves which causes the temperature of the food to increase
Why are microwaves used to communicate with satellites in space
Microwaves can pass through the earths atmosphere without being reflected or refracted
What is infrared used for
To cook food in ovens
To be emitted by electrical heaters
For cameras
Why is infrared useful
The energy of infrared is easily absorbed by the surface of objects
What is visible light used for
Communication using fibre optics
What are optical fibres
Thin strands of glass which can be used to transmit pulses of light to carry information
Why can light carry a lot of information
Short wavelength
What is ultra Violet used for
Energy-efficient lightbulbs
Suntanning
What is ultraviolet used for energy-efficient lightbulbs
The energy is absorbed by the internal surface of the bulb and it’s converted to visible light which requires much less energy than a normal lightbulb
What is the principal axis
When a ray passes through a lens without being Refracted
What is the principal focus
The point all the rays refract to
What is the focal length
The distance from the centre of the lens to the principal focus
What are the features of an object that is more than 2 focal lengths away from a convex lens
Object is diminished
Image is inverted
Real image
What are the features of an object between one and two focal lengths of a convex lens
Image is magnified 
Real image
Inverted 
What are the features for the ray diagram of a magnifying glass
Image is magnified
Image is upright
Image is virtual
When is the only time a convex lens produces a virtual image 
In a magnifying glass
How do you calculate magnification
Image height / Object height
What’s the features of a concave lens ray diagram
Image is diminished
Image is upright
Image is virtual
What is specular reflection
When all light rays reflect in a single direction 
What is diffuse reflection 
When light rays are scattered in all directions
Each colour on the spectrum of visible light has a narrow band of what two properties 
Wavelength and frequency
What does the colour of an object depend on 
Which wavelength of light are reflected transmitted or absorbed
How do coloured filters work
By absorbing specific wavelengths and transmitting other wavelength
What do transparent and translucent objects do to light 
Transmit light
What are objects that you cannot see through called
Opaque objects
All objects no matter what temperature emit and absorb what
Infrared radiation
What do the wavelength and intensity of radiation depend on
The temperature of the object
What does a perfect black body do
Absorb all of the radiation incident on it. This means no radiation is reflected or transmitted
What does the sun emit
Short wavelength radiation
Some of the sun’s radiation is reflected by the earth
the earth
When radiation is absorbed by the earths surface what happens
Thearths temperature increases and emits infared radiation into space
