Waves Flashcards
How fast do Electromagnetic waves travel?
The speed of light
What are the 7 distinct electromagnetic waves that make up the electromagnetic spectrum
- Radio Waves
- Microwaves
- Infrared
- Visible light
- Ultraviolet
- X-rays
- Gamma Rays
In order list out the Mnemoic
Remember My Instructions Visible Using X-ray Glasses
What are Radio Waves for?
used for sending radio and television signals. They are also used to control radio-controlled toys, like cars, boats and aeroplanes
radiowaves are also used in astronomy to find out about distant stars and galaxies by studying the radio waves they produce.
What are Microwaves?
Microwaves are used for communication e.g. mobile phones, WI-FI, devices like laptop computers all use microaves
Microwaves are also used for sending satellite signals e.g. GPS systems or satellite television
What are infrared waves?
Emitted by all warm objects, and are used for heating and to cook food in ovens, grills and toasters.
Also used for communications e.g. remote controls for televisions and stereos as well as sending internet and telephone signals along optical fibres.
Infrared waves can also be detected by infrared cameras so, often used by night vision cameras or thermal imaging cameras
What is visible light?
The only type of elelctromagnetic raditation which is visible to the human eye
it allows us to see, form images in cameras and video cameras.
Concentrated visible light emitted by lasers can be used to send internet and telephone signals along optical fibres.
Lasers can even be used in surgery, and to cut materials like wood and metals in a laser cutter
What is Ultraviolet waves?
UV waves are used in forensic science to help detect forged documents, like fake banknotes, passports or driving licenses
UV waves can be absorbed by some materials e.g. fluorescent inks in highlighter pens, making them glow brightly
They are also used to disinfect water by killing bacteria.
What are X-rays
commonly used to produce medical images of broken bones because they can pass through body tissues but are absorbed by bones
they are also used to sterilise medical equipment killing bacteria present before the instruments are used for surgery
Also used in airport security scanners and to detect broken pipes underground
What are Gamma rays?
Used to produce medical images and to serilise medical instruments
used to sterilise food, killing bacteria in fresh fruit and vegetables to increase their shelf life
Can also be used to detect and even treat cancer
What are the longest wavelengths?
Radiowaves have the longest wavelengths of all EM waves
Radiowaves have wavelengths ranging from thousands of metres down to around 30cm
This means they can easily travel around large objects like hills, mountains or buildings.
What determines a waves length?
Frequency
List the waves from longest to shortest
Radio, micro, infared, visible light, ultraviolet, x-ray, Gamma ray
When a resultant wave has a greater amplitude than the individual waves this is called?
Constructive interference
What a resultant wave has a lesser amplitude than the individual waves this is called?
Destructive interference
How do you calculate wavelength?
Wavelength (upside down y, in meters) = wave speed (v, in m/s) divided by frequency (f, in Hertz)
How do you calculate wave speed?
wave speed = frequency x wavelength
How do you calculate frequency?
frequency = wave speed divided by wavelength
What does one wave per second equal
One hertz per second
How do you measure wavelength?
the distance of the crest from one wave to another
How do you measure amplitude?
the rest position to the top of waves crest
What are the three types of radiowaves and their characteristics?
Long waves - can be transmitted over huge distances as they diffract (bend) around the curved surface of the earth
Short waves - travel long distances but are reflected from the ionosphere (an electrically charged layer of the earth’s upper atmosphere
very short waves - used for tv and fm radio travelling directly from transmitter to receiver (hills and tunnels can get in the way)
