Infrared, Microwave & Radio Waves
Applied Science: BTEC Level 3 National Extended Diploma, topic 1.7.7
Infrared Radiation
Infrared (or infra-red) radiation is one type of wave on the electromagnetic spectrum.
Uses
- Infra-red radiation is used in TV controls.
- Infra-red can also be used for security purposes, such as in intruder alarms by detecting body heat.
Risks
- Infra-red radiation can cause serious skin burns if emitted from high-intensity sources.
Explanation
- The frequency is high enough to excite particles in food. This increases their temperature.
- Infra-red cameras can detect a range of frequencies. These frequencies can be shown in different colours to depict images.
Microwaves
Microwaves are the 6th type of wave in the electromagnetic spectrum.
Uses
- Microwaves are used for the purpose of satellite communications (transmitting signals between stations on Earth and satellites).
- Microwaves are also used to transmit signal from a nearby phone mast (transmitter) to a mobile phone.
- Microwaves are absorbed by water, heating up the water in the process. This makes microwaves useful for cooking food because food contains lots of water.
Risks
- Because humans are largely made up of water, exposure to microwaves could have a harmful effect.
Safety
- We should always reduce any exposure to microwaves.
- As with X-rays, always have some sort of shielding between the source of microwaves and living tissue.
- An example of this is the protective shielding on microwave ovens.
Explanation
- Microwaves have a high enough frequency to penetrate the Earth’s atmosphere and to reach satellites.
- Microwaves travel in straight lines through the atmosphere. This makes them good for transmitting (sending) signals.
Radio Waves
Radio waves are used for radio and TV communications.
Uses
- Radio waves are used for radio and TV communications.
Risks
- At high intensities, radio waves can cause internal heating of living tissue with potentially harmful effects.
Explanation
- Because radio waves have long wavelengths, they can be transmitted (sent) around the Earth’s surface and around buildings without interference.
Test yourself on Infrared, Microwave & Radio Waves
What type of wave is infra-red radiation?
What is an example of a safety measure used when dealing with microwaves?
Microwaves transfer energy to water molecules and can cause severe burns. How are microwave ovens safe to use?
Which one of these is a use of radio waves?
Which statement about radio waves is true?