# P1 Electromagnetic Waves

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• Created by: KAustria
• Created on: 11-06-14 12:51
These are electric and magnetic disturbances. They travel as waves and move energy from place to place.
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What do electromagnetic waves have in common when travelling through a vacuum? What are there differences?
They can all travel through a vacuum at the same speed. But they have different wavelengths and different frequencies.
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What are the electromagnetic waves called together and how do you group them?
The collection of waves is known as the electromagnetic pectrum and they are grouped according to their wavelength and frequency.
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What electromagnetic wave has the shortest wavelength and the highest frequency?
Gamma Rays
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What is the shortest wavelength a gamma ray can have?
10^-15 m
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What electromagnetic wave has the longest wavelength and the lowest frequency?
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What length can radio waves exceed?
10,000 m
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The higher the frequency of an electromagnetic wave the ___ energy it transfers.
More
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order the elctromagnetic waves from the lowest frequency to the highest?
1. Radio waves 2. Microwaves 3. Infrared Radiation 4. Light 5. Ultraviolet 6. X rays 7 Gamma Rays
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Order the electromagnetic waves from the highest frequency to the lowest frequency?
1. Gamma Rays 2. X rays 3. Ultra violet 4. Light 5. Infrared Radiation 6. microwaves 7 Radiowaves
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How many waves are there in the electromagnetic spectrum?
7
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IN what wave speed do electromagnetic waves travel through space in?
300 million m/s
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How can you calculate wave speed using frequency?
V 300 000 000 m/s = Frequency Hz x Wavelength in m
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What electromagnetic ave can we detect with our eyes?
Visible light
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How can we see different colours?
Due to the different wavelength of visible light
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What can visible light be used in?
Photogrpahy
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Remote control devices such as Tvs, and CD players
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What are microwaves used in?
Commnication - send signals to and from satellites and within mobile networks
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How come microwaves are able to be used in communication?
This is because they are able to pass through the atmosphere
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These transmit radi and TV programs and carry mobile phone signals.
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Which have the longer wavelengths, microwaves or radiowaves?
Microwaves
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They can penetrate your skin and are absorbed by body tissue. This can heat internal organs and may damage them.
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How can infrared radiation harm the body?
It is absorbed by the skin and too much can burn you skin.
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Describe how radio waves work in communication
1. An alternating voltage applied to an aerial emits radiowaves with the same frequency as the voltage 2. Then the waves are recieved they produce an alternating current in the aerial with same frequency as the radiation received.
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What are radio and microwave spectrum split up into?
bands which are used for differeent communication purposes.
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The shorter the wavelength the ____ information it can carry
More
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The shorter their range the ___ they spread out
less
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What type os wave does a mobile phone use?
ON the border bwteen radio waves and microwaves but they are usually referred to as microwaves.
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What are optica fibres?
Very thin glass fibres. They are used to transmit signals carried by visible light or infrared radiation.
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How do signals from infrared radiation and visible light travel down an optical fibre?
By total internal Reflection.
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Why are optical fibres more useful in communication than radio and microwaves?
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What is the doppler effect?
The change of wavelength (and frequency) of the waves form amoving source due to the motion of the source towards or away from the observer.
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What happens when the source of the waves moves away from the observer?
The wavelength increases and the frequency decreases.
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What happens when the source of the wave moves towards the observer?
The wavelength decreases and the frequency increases.
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How can the doppler wave be demonstrated?
Through sound waves.
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What are galaxies?
large colelction of srs
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What is red shift?
the increase in wavelength of electromagnetic waves emitted by a star or galaxy due to its motion away from us. The faster the speed of the star, the greater the red shift is.
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The further away the galaxy, the ___ its red shift
bigger
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what does red shift suggest?
This suggests that distant galaxies are moving away from us, and the most distant galaxies are moving away the fastest. So the universe is expanding in all direction
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What is the Big Bang theory?
The belief that wall matter was concentrated to one point. Then the Big Band occured which produced high energy gamma radiation. As the universe expanded this would have become low energy radiation.
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what is CMBR?
Cosmic Microwave radiation produced by the big ban which was discovered by scientists to have been present in every direction.
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What happens to the wavelength of radiation as it changes from gamma to microwave?
IT has increased.
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## Other cards in this set

### Card 2

#### Front

What do electromagnetic waves have in common when travelling through a vacuum? What are there differences?

#### Back

They can all travel through a vacuum at the same speed. But they have different wavelengths and different frequencies.

### Card 3

#### Front

What are the electromagnetic waves called together and how do you group them?

### Card 4

#### Front

What electromagnetic wave has the shortest wavelength and the highest frequency?

### Card 5

#### Front

What is the shortest wavelength a gamma ray can have?