Waves 2 Flashcards
2 types of wave
Transverse
longitudinal
1 example of longitudinal waves
Sound waves
All waves transfer…from one place to another
Energy
True or false, all waves require a medium to travel in e.g air/ a solid
False
All longitudinal waves require a medium to travel in
Only some transverse waves require a medium to travel in
Amplitude meaning
Maximum displacement of a point on a wave away from its undisturbed position
Amplitude is the ….of a point on a wave away from its…
Maximum displacement
Undisturbed position
Amplitude is the maximum displacement…….undisturbed position
of a point on a wave away from its
Wavelength is the distance from a point on one wave to the equivalent point on the…
Adjacent wave
Frequency meaning
Number of waves passing a point each second
50Hz means how many waves are passing a point each second
50 waves
If 20 waves pass a point each second what is the frequency
20Hz
As frequency is the number of waves passing a point each second
Period of a wave meaning
Time taken for wave to pass a point (in seconds)
Frequency vs period
Frequency is number of waves passing a point each second
Period is time taken for a wave to pass a point
Unit for period of a wave
Seconds
Wave speed meaning
Speed at which the wave moves through a medium/ speed at which energy is transferred through a medium
Wave speed is the speed at which a wave moves through a…./ the speed at which energy is transferred through a…
Medium
Describe Method to determine speed of sound waves in air
1) lay out 500m tape measure in straight line on ground in the open air
2) person A stands at 0m mark holding pair of cymbals, person B stands at the 500m mark with timer
3) person A starts timing when they see person B clash the cymbals together
4) person A stops timing as soon as they hear the sound of the cymbals
5) calculate speed of sound wave by doing distance (500m)/ time taken
Errors: different people have different reaction times (some people I’ll be able to start the timer quicker after seeing the cymbals clash together than others which will effect the time recorded)
It takes a fraction of a second between seeing the cymbals clash and starting the timer and between hearing the sound and stopping the timer (so the time won’t be fully accurate)
2 improvements:
Repeat investigation with lots of different people being in charge of the timer and calculate the mean time on the timers
Use longer distance between person A and person B to make the time between person A seeing the cymbals clash and hearing them longer so that the time is more accurate
For method to find speed of sound waves in air what are 2 sources of error
Different people have different reaction times so some people may take longer than others between seeing the cymbals clash together and stating the timer
It takes a fraction of a second between seeing the cymbals clash together and pressing the timer and hearing the cymbals and stopping the timer so that time recorded won’t be fully accurate
2 improvements to method of finding speed of sound waves in air
Repeat investigation at least 9 times with different people timing and calculate mean time
Increase distance between person A and person B
3 things that can happen to a wave when it meets a new medium
1) is transmitted
2) energy is absorbed
3) reflected
Which ray and angle comes first out of reflection and incident
First incident ray and angle of incidence
Second reflected ray and angle of reflection
Range of human hearing
20Hz
20,000Hz
Lowest frequency humans can hear
20Hz
Highest frequency humans can hear
20,000Hz
What 2 key things change when a wave passed from one medium to another
Wave speed
Wavelength
Which 2 things change out of wave speed, frequency and wavelength when a wave travels from one medium to another
Wave speed
Wavelength
(Not frequency)
Connection between frequency and pitch
Higher frequency= higher pitch
Lower frequency= lower pitch
Connection between volume and amplitude
Louder= bigger amplitude
Quieter= smaller amplitude
Sound waves can only move through a…..e.g air/ a solid
Medium
True or false, sound waves can travel through a vacuum
False
There must be a medium so that particles can vibrate
Specific name for when sound waves are reflected
Echo
An echo is when sound waves are..
Reflected
Ultrasound is sound waves with a frequency greater than…
20,000Hz
3 uses of ultrasound
Producing images of internal organs e.g kidneys
Producing images of a foetus
Industrial imaging to show hidden defects
Out of the crust, mantle, outer core and inner core which is solid and which is liquid
Crust, mantle and inner core= solid
outer core= liquid
Is the outer core of the earth solid or liquid
Liquid
But the mantle, inner core and crust are all solid
Are the crust, mantle and inner core of the earth all liquid or solid
Solid
(Outer core is liquid)
2 main types of seismic waves
P waves
S waves
3 differences between P waves and S waves
P waves are longitudinal, S waves are transverse
P waves can travel through solids and liquids, S waves can only travel through solids
P waves travel faster than S waves
Which travel faster out of p waves and S waves
P waves are faster
Do seismic waves travel in straight lines or curved paths
Curved paths
(Due to different densities of the earth so the waves refract)
Name for zones on earth where P waves/ S waves can’t be detected
Shadow zones
EM waves transfer energy from the….of the wave to the…
Source
Absorber
Which EM wave has the lowest frequency and longest wavelength
Radio waves
Which EM waves has the highest frequency and shortest wavelength
Gamma rays
True or false, EM waves need a medium to travel in
False
They don’t need a medium to travel in so can travel through vacuums
All EM waves travel at the same …through a vacuum
Speed
True or false, all EM waves travel at the same speed through a vacuum
True
(300 million m/s)
(3x10^8 m/s)
All EM waves travel at the same speed through a vacuum which is….m/s
300 million
(300,000,000)
2 Uses of radio waves
Radios
TVs
2 uses of microwaves
Satellite communication
Cooking food
3 Uses of infrared radiation
Thermal image cameras
Electric heaters
Toasters (cooking food)
One key use of visible light
Fibre optic communication
2 key uses of Ultraviolet rays
Sun tanning
Security marking
Which type of EM wave causes premature skin ageing
Ultraviolet rays
Which 3 types of EM waves can cause mutations and cancer
Last 3 waves
(UV rays, X rays, gamma rays)
2 uses of X rays and gamma rays
Medical imaging and treatment
1 hazard of infrared rays
Can cause burns
1 hazard of visible light
Can damage eyesight
2 hazards of UV rays
Can cause cancer
Can cause premature skin ageing
When waves slow down do they bend towards or away from the normal
Slow down= towards normal
When waves speed up do they bend towards or away from the normal
Speed up= away
(Fast people can get away quicker)
When atoms are heated what happens to electrons in terms of the energy levels
Electrons move from one energy level to a higher energy level
Describe how heating an atom generates an EM wave
When atom is heated, electrons move from one energy level to a higher one
When the electron returns to its original energy level it generates an EM wave
2 hazards that ultraviolet rays, x rays and gamma rays all share in common
Can cause mutations and cancer
X rays and gamma rays are also ionising
Ultraviolet rays can also cause premature skin ageing
Do waves travel faster in air or glass
Air = faster
Glass= slower
Differences between EM waves and sound waves
EM waves are transverse, sound waves are longitudinal
EM waves can travel through a vacuum, sound waves can’t
EM waves travel faster than sound waves
EM waves have greater frequencies than sound waves
One difference between sound waves and EM waves is that EM waves have higher..
Frequencies
Apart from being used for toasters and electric heaters, another use of infrared radiation is…
Thermal image cameras
What shape is a convex lens
Leaf shape
Which type of lens is leaf shaped
Convex lens
What is the focal length
Distance between centre of lens and principle focus
The distance between the centre of the lens and principle focus is called the…
Focal length
What letter is used to represent principle focus
F
What does F represent (to do with lenses)
Principle focus
How to draw ray diagram for convex lens (leaf shaped lens)
1) Draw straight line from top of object passing straight through centre of lens
2) draw straight horizontal line from top of object up to lens
3) draw straight line from where 2nd line has ended passing through Principle focus (F) on other side of lens
Where 2 lines meet draw vertical line up to axis and this is the image
Name for axis used in ray diagrams
Principal axis
Example of when convex lenses produce virtual image
Magnifying glasses
Which type of lens out of convex and concave do magnifying glasses use
Convex
Name for type of lens which is non leaf shaped
Concave lens
Do convex lenses make parallel light rays converge or diverge
Converge (move inwards together)
Which type of lens makes parallel light rays diverge (spread out) when they hit it
Concave
Which type of lens makes parallel light rays converge when they hit it
Convex lens
Name for point where all parallel light rays converge to when they hit a convex lens
Principle focus
How to draw ray diagram for concave lens
1) draw straight line from top of object passing straight through centre of lens
2) draw horizontal line from top of object up to lens
3) draw straight line starting from end of 2nd line and passing through principle focus (F) (usually this point is still on the left hand size of the lens so the line must be dotted)
4) where 2 lines meet draw vertical line connecting this point to the axis and this is the image
6 potential words to use when describing image formed from convex/ concave lenses
Diminished/ magnified
Upright/ inverted
Virtual/ real
For a concave lens you can always describe the image as …, ….and …
Diminished
Upright
Vertical
(Concave lenses are DUV)
True or false, all type of reflection produce an image
False
Specular reflection produces an image (involves smooth surfaces) but diffuse reflection doesn’t produce an image (involves rough surfaces)
2 type of reflection depending on type of surface
Specular= smooth surface (image formed)
Diffuse= rough surface (image not formed)
Coloured filters work by…specific wavelengths and…other wavelengths
Absorbing
Transmitting
Does a red filter absorb red and transmit all other wavelengths or transmit red and absorb all other wavelengths
Red filter= absorbs all colours of visible light except red, red is transmitted
When using a red colour filter only what colour is transmitted (all other colours are absorbed)
Red
When using a green filter only what colour is transmitted (all other colours are absorbed)
Green
When talking about coloured filters, what 2 things can happen to visible light when it hits the filter
Be absorbed
Be transmitted
When talking about an object, what 2 things can happen to visible light when it hits the object
Be absorbed
Be reflected
(E.g a red object absorbs all colours except red which is reflected)
When light hits both an object or coloured filter it can be absorbed. But what’s different about the other thing that can happen to light when it hits an object compared to coloured filter
Coloured filter- light transmitted (to see it e.g red filters transmit red so we can see red)
Object- light reflected (to see it e.g red object reflectes red so we can see red)
What colour does an object appear if no light is reflected
Black
What surface is the best absorber and emitter of infrared radiation
Matt black
All objects (no matter what temperature) emit and absorb…
Infrared radiation
True or false, all objects emit and absorb infrared radiation
True
Both the wavelength and intensity of radiation depend on what
Temperature of object
Both the…and…of radiation depend on the temperature of the object
Wavelength
Intensity
Do very hot objects emit longer or shorter wavelength radiation than cooler objects
Shorter wavelength
Which out of hotter or cooler objects emits more intense radiation
Hotter objects
A perfect black body…all the radiation incident on it (that hits it)
Absorbs
A perfect black body absorbs all…
Incident radiation on it
(Radiation that hits it)
If an object is…than its surroundings then it emits more radiation than it absorbs so its temperature will decrease
Hotter
If an object is hotter than its surroundings then it emits more radiation than it absorbs so its temperature…
Decreases
If an object is hotter than its surroundings it…more radiation than it…so its temperature will decrease
Emits
Absorbs
If an object is…than its surroundings then it absorbs more radiation than it emits so its temperature increases
Cooler
If an object is cooler than its surroundings then it…more radiation than it…so its temperature increases
Absorbs
Emits
The only way the earth can lose or gain energy is by..or…radiation
Absorbing
Emitting
The only way the sun can lose or gain energy is by emitting or absorbing…
Radiation
The only way the sun can lose or gain energy is by…
Emitting or absorbing radiation
The only way the sun can lose or gain energy is by…
Emitting or absorbing radiation
