Electromagentic waves Flashcards
Transverse wave
Particles that oscillate at a right angle to the direction the wave is travelling.
Electromagnetic waves
They are Transverse waves. Their oscillations are changes in electrical and magnetic fields at right angles to the direction of wave travel.
Electromagnetic spectrum
It is all of the different type of light waves. They all travel in the speed of light 3 x 10^8. All EM waves travel through a vacuum.
Gamma Rays
Have a short wavelength and high frequency. They can ionise molecules and cause cell/tissue damage. This because they carry the most energy. Therefore, they are used to sterilise medical equipment and treating/detecting cancer.
X - Ray
X-rays have a lower frequency than gamma rays, and so are lower in energy. But they are still highly ionizing to cells. They penetrate soft materials (like body tissues). Low energy X - Rays are often used for medical X - rays. High energy X - rays are to treat cancer.
Ultraviolet
Ultraviolet is light is used in disinfection and fake tanning. Exposure to too much ultraviolet light can cause skin burns and skin cancer.
Visible Light
Visible light is the light we can see. It is used in fibre optic communications, where coded pulses of light travel through glass fibres from a source to a receiver.
Infrared
Infrared light has frequencies which are absorbed by some chemical bonds. The internal energy of the bonds increases when they absorb infrared light, which causes heating. This makes infrared light useful for electrical heaters and for cooking food. We can not see it but it is detected by cameras
Microwaves
High frequency microwaves have frequencies which are easily absorbed by molecules in food. Therefore they are mainly used for cooking food and satellites for communication.
Radio Waves
Radio waves can be produced by oscillations in electrical circuits. They are transmitted easily through air. They do not cause damage if absorbed by the human body. These properties make them ideal for communications.
