Unit 1: 6 - Electromagnetic Waves Flashcards
What are electromagnetic radiations?
Electric and magnetic disturbances.
What approximate wavespeed do all electromagnetic waves travel through a vacuum at?
300,000,000 m/s.
What electromagnetic waves have the shortest wavelength and highest frequency?
Gamma.
What electromagnetic waves have the longest wavelength and lowest frequency?
Radio waves.
How small wavelengths can gamma rays have?
10^-15m.
How large wavelengths can radio waves have?
1-10km.
Give an example of a device that uses visible light.
A camera.
Give an example of a device that uses infrared radiation.
Remote controls (for TVs etc.).
Give an example of a device that uses microwaves (apart from the obvious…).
Satellites (and mobile phones) to provide mobile phone networks.
Give an example of a device that uses radio waves.
Radios, TV signal generators, phone transmitters.
Can microwaves and radio waves penetrate skin?
Yes (and they can burn you or damage internal organs).
The radio and microwave spectrum is divided into different…
Bands.
The shorter the wavelength, the ____ information they can carry.
more
The shorter the wavelength, the ____ they can spread out.
less
Give a possible health concern about using mobile phones.
Microwaves can heat the brain, which is rumoured to damage it and cause cancers.