P1.6 Electromagnetic Waves Flashcards
Name the electromagnetic waves from shortest wavelength to longest.
Gamma X-rays Ultra-violet (Visible) Light Infrared Microwaves Radio
What are the features of gamma waves on the em spectrum?
High frequency
Short wavelength
High energy
What type of of wave are all electromagnetic waves?
Transverse
What is the speed of electromagnetic waves?
3 X 10 to the power 8 m/s
How do you work out the frequency of a wave?
Speed / wavelength
What are the uses of radio waves?
Connects devices like Bluetooth or wireless connections
Wifi, radio and to
What are the uses of microwaves?
Communications Beam signals (can heat food)
What are the uses of infrared?
Optical fibres to transmit signals like a remote
Can see people in darkness
What are the uses of visible light?
Cameras - digital and film
Produce pixels
What are the dangers of radio waves?
Very high frequencies in radar towers
What are the dangers of microwaves?
Cooks through tissues and can dry out your body
Internal tissue bleeding
What’s the danger of infrared?
Can burn you
What’s the danger of visible light?
Blindness
What can’t radio waves travel through?
The atmosphere
What’s the Doppler effect?
As an ambulance travels forward: the wave front is compressed, decreasing its wavelength and increasing the frequency.
The wave behind is stretched out, increasing its wavelength and decreasing its frequency.
What waves can be the Doppler effect?
Light
Sound
Microwaves
What’s red shift?
Light from galaxies is shifted towards the red end of the spectrum, increasing wavelength.
This proves they’re moving away from us and is a huge piece of evidence to show the universe is expanding.
What’s the Big Bang theory?
The universe started at a very small single point (singularity). Nothing else anywhere. This contained all the matter and energy.
There was a big explosion and the matter expanded outwards in all directions.
As it began to cool stars and planets began to form.
The universe has been expanding ever since.
What’s CMBR?
Cosmic microwave background radiation
Key piece of evidence for the Big Bang. CMBR is electromagnetic radiation remaining from the Big Bang explosion and fills the whole of the universe.
Why are optical fibres useful?
They carry much more information and are more secure than radio waves and microwave transmissions.
What’s blue-shift?
Indicates a galaxy is moving towards us
How do we know the universe is expanding?
Red shift proves all galaxies are moving away from each other meaning the universe must be expanding.
What is the range of wavelength of electromagnetic waves?
10 to the -15 m
To
10 to the 4 m (10000m)
