P5 Flashcards
What is amplitude ?
Amplitude is the displacement from the rest position to the Crest/trough perceived as sound volume
What is wavelength?
Wavelength is the length of the full cycle from Crest to Crest/compression to compression
What is frequency?
Frequency is the number of complete waves/cycles passing point per second measured in hertz (Hz)
What is the period?
The period is the number of seconds it takes for one full cycle which is one divided by frequency
Definition of a transverse wave
transverse wave is a wave that the vibrations are perpendicular to the direction waves travel
Give three examples of transverse waves
EM waves, s waves, ripples
Definition of a longitudinal wave
A longitudinal wave has vibrations which are parallel to the direction of waves travel they are made up of compressions (high-pressure) and rarefractions (low-pressure)
Give two examples of longitudinal waves
Soundwave and P-waves
Wave speed =
Frequency X Wavelength
Describing experiment to find the frequency of a wave
1) Place a piece Whitepaper with a pencil line across it under ripple tank .
2) Turn it on and film the shadows on the paper for 10 seconds.
3) Slow mo the footage and count the number of ways.
4) Divide by 10 to find the frequency.
Describing experiment to find the wavelength of a wave
1) Put a piece of white paper with a ruler on it under a ripple tank .
2) Turn it on and take a picture.
3) Measure the distance between the first five waves and divide by 5 to get the wavelength
Describe an experiment to find the wave speed of a wave
1) Place a piece of white paper with a ruler along one edge under ripple tank .
2) Turn it on and take a picture.
3) Measure the distance between the first Five waves and divide by 5 to get the wavelength.
4) Then remove the ruler and draw a pencil line across the piece of paper film the shadows on the paper for 10 seconds.
5) slow mo the footage and count the waves.
6) Divide by 10 to find the frequency.
7) Then use the equation wave speed =frequency X wavelength .
Which three things can happen when wave meets a boundary?
1) Absorption – the energy is transferred into the second materials energy store
2) transmission – can travel through the new material (often refracted)
3) reflection
Angle of incidence=
Angle of incidence=angle of reflection
What is white light ?
Why it like it is a mixture of different colours of light with different wavelengths
Definition of specular reflection
Specular reflection is when all rays are reflected in a single direction by smooth surface producing a clear reflection
Definition of scattered reflection
scattered reflection is when rays are reflected in all different directions to different normals which doesn’t produce a clear reflection
Describe practical to investigate reflection
1) Draw a line across the piece of paper and place a plane mirror so it lines up with the solid line.
2) Draw dotted line (the normal) at 90° to the solid line
3) Use a ray box to shine a beam of light where the normal hits the mirror.
4) Trace the incidence and reflected ray
5) Measure the incidence and reflected angles you will find that they are equal
Definition of refraction
Refraction is the change of direction of a wave due to a change in speed when moving from one medium to another
What changes when a wave refracts and why
The wavelength of a wave changes when it refracts because the frequency never changes and as the wave speed changes and wave speed is equal to frequency times wavelength thus the wavelength must change
Do EM waves speed up or slow down when travelling into a more dense material ?
EM waves slow down when they travel into more dense materials
Do you soundwave speed up or slow down when travelling into more dense materials ?
Soundwave speed up when travelling into more dense materials
If a wave speeds up does it bend towards or away from the normal
When a wave speeds up it will bend away from the normal
If a wave slows down will it bend away from or towards the normal?
If a wave slows down it will bend towards st he normal
Which colours refractive the most and why
Violet retracts the most because it has the shortest wavelength
Describe an experiment to investigate the refraction of light
1) place a glass prism on a sheet of white paper
2) using a ray box and a coloured filter to shine a beam of coloured light at the prism
3) trace the incidence Ray and merging ray and label the colour
4) repeat using different coloured filters and you will find violet retracts the most and red retracts the least
What happens when white light is shone through a triangular prism?
The white light splits into the different colours of light because they all refract by different amounts
Complete
The _______ Ray and the ______ Ray are always parallel
The incidence Ray and the emerging ray are always parallel
Explain how sound is made by Speaker travels through the air and then through solid objects
1) soundwave are created by vibrating objects. Electric signal causes a paper diagram to vibrate causing the air particles vibrate creating a soundwave
2) soundwaves are longitudinal waves they travel through the air as a series of compressions and rarefractions
3) when the soundwave hit a solid object it causes the particles vibrate vibrating particles knock other particles passing on the energy causing them to vibrate passing the sound to the object
Why can’t sound travel through space?
sound cannot travel in space because space is a vacuum and there aren’t any particles to vibrate
Does the frequency or wavelength or neither change as a soundwave passes from one medium to another
as sound speed changes as it passes from one medium to another ( for example sound travels faster in solid objects ) then as wave speed is equal to the frequency times wavelength the wavelength must also change as the frequency of sound doesn’t change as this would change the pitch
What are echoes?
Echoes are reflected soundwave s
How does the ear help us to hear sound ?
1) soundwave that meet the eardrum cause it to vibrate
2) the vibrations are passed on to the ossicles (tiny bones in the ear)
3) the vibrations passed through the semicircular canal
4) when the vibrations meet the cochlea turns them into electrical signals are sent to the brain
What is ultrasound and why is it useful ?
Ultrasound is sound with the frequency above 20 kHz and it is useful in medicine because it can pass through the body that is partially reflected at boundaries between tissues . By calculating the distance and ultra soundwave has travelled before it meets a boundary between tissues and image can be processed by computer for example of the foetus
Which other areas besides medicine is ultrasound useful in?
Ultrasound can also be used to find flaws in materials for example underground pipes
What is sonar and why is it useful ?
So now the type of ultrasound with a much longer range which is fine distances between boundaries such as ownership to the sea floor a pulse of the ultrasound is sent at a specific speed at a boundary and it is timed partially reflected at the boundary and the time is in gave over and the formula distance is equal to speed times time is used to find the distance
What are electromagnetic waves ?
Electromagnetic waves vibrations of electric and magnetic fields
What type of waves electromagnetic waves ?
Electromagnetic waves are transverse waves
Why do the electromagnetic waves with the shortest wavelength have the highest frequencies and vice versa
As all electromagnetic waves travel at the same speeding and wave speed is equal to frequency times wavelength those with a shorter wavelength must have a higher frequencies to have the same wave speed as those with the longer wavelengths which have a lower frequencies
Which electromagnetic waves transfer the most energy ?
Electromagnetic waves with the higher frequencies transfer the most energy
List all the electromagnetic waves and their wavelengths
radio waves (1m-10^4m) Microwaves ( 10^-2m) Infrared (10^-5m) Visible light (10^-7m) Ultraviolet light (10^-8m) X-rays (10^-10m) Gamma rays (10^-15m)
Which has the longest wavelength of radio waves of gamma rays
radio waves has the longest wavelength and the lowest frequency
What implications the radio waves have on human health ?
Radio waves are transmitted straight through the body without being absorbed
What are radio waves are used for ?
Radio waves are used to transmit radio and terrestrial TV signals by including the information (for example a TV show) in an alternating-current which is transmitted as a radiowave and then induces an alternating-current in the receiver (for example an aerial)/. TV, FM and Bluetooth use short wavelength radio waves and MW and LW radio transmissions using medium and long wavelength of radio waves .
What implications do microwaves have on human health?
Some wavelength of microwaves can be absorbed by the body and heat cells.
What are microwaved used for?
Microwaves are used for heating food because most foods contain a lot of water molecules and water molecules absorb the energy of microwaves which heats the food. Microwaves are also used to communicate with satellites in space the TV or mobile phones because they can pass through the earths atmosphere without being reflected or refracted
What implications does infrared having human health ?
Infrared can be reflected or absorbs by the skin and can cause heating ourselves or skin burnz
What are infrared waves used for
Infrared is used in cookers and heaters because the infrared energy is easily absorbed by the surface of objects. Infrared is also used in nightvision cameras which detect infrared radiation and turn it into an electrical signal which is displayed on screen as picture . Infrared cameras can be used in medical imaging because infected or injured areas give of more infrared radiation
What implications can ultraviolet light have on the human body
Ultraviolet light can be absorbs by the skin as ionising radiation which can lead to genetic mutation, cancer, tissue damage and radiation sickness. UV rays can also damage to your name skin cells is why it is important to wear sunscreen
What are ultraviolet waves used for
ultraviolet waves can be used in fluorescent lamps which contain chemicals which absorb UV light and emit visible light which are energy efficient . They are also used in security pounds which are invisible but glow under UV light.
What is visible light used for?
Visible light is used in optic fibres which carries data long distances by bouncing light off a very narrow core which is used in telephone cables, Internet cables and medical purposes to see inside the body
What implications can x-rays have on human health
X-rays are ionising and can cause genetic mutations, cancer and deep tissue damage
What are x-rays used for ?
X-rays are used to view internal structures because they message transmitted by soft tissues but absorbed by bones metals so can be used to diagnose bone fractures and dental problems . However some x-rays are absorbed by soft tissues meaning you use a lot of ectasia can produce a high resolution 2D/3D image of hard or soft tissues in the body called a CT scan
What implications can GammaRays have on human health
Gamma rays are ionising say can cause genetic mutations, cancer and deep tissue damage
What are GammaRay is used for ?
Gamma rays are used to sterilise medical instruments and food . GammaRay is also used to treat cancer by targeting radiation cancer cells to kill them . Finally gamma rays can be used to see how the body is working example radiotracer is ( radioactive isotopes which emit gamma rays ) can be swallowed or injected into a patient the gamma rays are then detected by gamma camera which can detect cancerous tumour which uses up more energy and shows up as a bright spot.
Definition of opaque
Opaque is an object does not transmit light and will only absorb some wavelengths of light and reflected others the colour of an opaque object depends on which wavelengths are reflected
Which of the three primary colours
red green and blue are three primary colours they cannot be made by mixing other colours
Is a banana is yellow which wavelengths of light could it be reflecting
a banana coupe yellow because it’s reflecting yellow light or it could appear yellow because it’s reflecting both red and green light
Which wavelengths of light reflected by White objects
White objects reflect all wavelengths of light
Why do black objects appear black
black objects appear black because they absorb all wavelengths of light
Definition of transparent /translucent
transparent and translucent object or objects that can transmit lights they can also absorb and reflect light stop . Colour of the wavelengths of light most strongly transmitted
Which wavelengths of light is transmitted by a primary colour filter
A primary colour filter only transmits that colour the rest of the light is absorbed
Which wavelengths of light without a filter which is a mixture of colours for example cyan transmit
a filter which is a mixture colour selector in both wavelengths that make up the colour and the colour itself for example a cyan filter will transmit wavelengths of blue, green and cyan
What do concave lens do to the rays of light
Concave lens causing rays of light to diverge (spread out)
What type of lens is used the people who suffer from shortsightedness
Concave lenses are used in glasses for shortsightedness
What do convex lenses do to rays of light
Convex lenses cause rays of light to converge (move together)
Which type of lens is used in glasses for people who suffer from longsightedness
Convex lens are used in glasses for people who suffer from lomgsightedness
Which two types of images and lenses form
lenses can you perform a real image like the one formed in the retina or a virtual image like the image formed in a mirror
