P13 Electromagnetic Waves Flashcards
What order does the electromagnetic spectrum go in
In order of decreasing wave length and increasing frequency and energy
What is the electromagnetic spectrum made up of
Radio waves Microwaves Infrared radiation Visible light (red to violet) Ultraviolet X-rays and Gamma rays
What wavelength can the human eye detect?
Visible light (ranges from 400nm to above 700nm)
How do electromagnetic waves transfer energy
From a source to an absorber
Wave speed equation:
V= frequency x wavelength
What colours does whit light contain
All the colours on the visible light spectrum
Infrared radiation uses?
Carrying signals from remote control handsets and inside optical fibres
Microwaves uses?
Carry statelite TV programmes and mobile phone calls.
Heating food
Radio waves uses?
Radio and TV broadcasting, radio communications and mobile phone calls
What is mobile phone radiation
Microwave radiation, and is also radio waves at near micorwave frequencies
Why are radio waves of different frequencies used?
They have different purposes, because the wavelength (and so the frequency) of waves affects: how far they travel, how much they speard out, and how much information they carry.
How are microwaves used for communication?
Used for satellite TV signals
Are mobile phones safe to use?
Further research is required to evaluate wether or not they are safe, however micro and radio waves can heat the internal parts of people’s bodies and infared radiation can cause skin burns.
What are Carrier waves?
Waves that are used to carry information. They do this be varying their amplitude
Optical fibres?
Very thin transparent fibres that are used to transmit communication signals by light and infrared radiation. Light rays cant escape when they reach the surface of the fobre they just reflect back into the fibre.