Region of Electromagnetic Spectrum:-
Infrared
Uses in Domestic Situations:-
Infrared is used for all remote controls of TVs and videos. It’s ideal for sending harmless signals over short distances, without interfering with the other radio frequencies. They’re also used in toasters to heat the bread.
Dangers in domestic situations:-
Over-exposure to infrared causes damage to cells, like Microwaves. It’s this over-exposure that causes sunburn.
Region of Electromagnetic Spectrum:-
Ultraviolet
Uses in Domestic Situations:-
Ultraviolet light is what gives us our tan from the sun, or from sun beds. They’re also used in fluorescent tubes.
Dangers in Domestic Situations:-
Ultraviolet rays can cause skin cancer, if you spend too much time in the sun. Sun beds give out less harmful rays than those from the sun.
X-Rays in Medicine:-
X-rays can pass through most solids with very little of their energy being absorbed because they have very short wavelengths. Photographic film is used to take X-ray pictures of the body – the developed film appears dark where the x-rays touched it, meaning they don’t pass through bone or metal.
X-Rays are dangerous, as they can cause cancer, so radiographers have to wear lead aprons and stay behind a lead screen to keep their exposure to X-rays to a minimum.
Although X-Rays are dangerous, they are also used to treat skin disorders, such as skin cancer.
Gamma Radiation in Medicine:-
Gamma radiation has even shorter wavelengths than X-radiation. It penetrates tissues easily and has a great ionising power. It is therefore very dangerous to all living things. Gamma rays can cause cancers or even kill cells. Strangely, cancers can also be caused by killing cancerous cells with the gamma radiation, in small doses. This is called radiotherapy.
As well as being used to treat cancer, they’re also used to sterilise medicinal instruments by killing the bacteria that may on them.
Radio Waves:-
The waves with the longest wavelengths from the electromagnetic spectrum are radio waves (and TV waves). They are produced in a transmitter aerial by alternating electric currents. The waves pass through the air with the same frequency as the frequency of the current. They are then picked up by a receiving aerial with converts them back to alternating current with the same frequency of the wave. A radio converts this to sound.
Different radio stations produce waves with different wavelengths and frequencies. Radio waves can travel long distances, despite the Earth’s curve as they can reflect from the ionosphere (a layer of charged particles in the upper atmosphere).
Microwaves:-
Some microwaves are used for satellite communications because they have short wavelengths (similar to radio waves) and they can pass easily through the atmosphere. Because they travel in a straight line, they can easily be focused on the satellite by a concave dish transmitter. The microwaves are then re-routed by the satellite to a satellite dish, which by focusing them onto a transducer changes the waves to an electrical signal.
Infrared:-
Infrared is used for night-vision equipment. This works by detecting heat radiation giving off by all objects, even during the night. It then turns it into an electrical signal, which is displayed on a screen as a clear picture. The brightness of which the object appears is proportional to the hotness of the object.
