Contents
Key Stage 4
Meaning
Radiowaves are the lowest frequency and longest wavelength electromagnetic waves.
About Radiowaves
- Radiowaves transmit the least energy of all the electromagnetic waves.
- Radiowaves are transverse waves.
- Radiowaves can travel through a vacuum as well as through gases in the Earth's atmosphere.
- The speed of radiowaves through a vacuum is 300,000,000m/s.
As a wave radiowaves can be:
- Transmitted - Radiowaves can pass through a medium.
- Absorbed - The energy transferred by radiowaves can be taken in by certain materials, particularly metals.
- Reflected - Radiowaves can bounce off an interface between two media.
- Refracted - Radiowaves can change direction when they cross the interface between two media.
Unique Properties
- Radiowaves can cause alternating currents in metals.
- Radiowaves can pass through many non-metals unaffected.
Making Radiowaves
- Radiowaves are made by alternating currents. This can be used to broadcast signals. The radiowaves will then induce an alternating current in an antenna.
Applications
- Radiowaves can be used in satellite communication as well as radio broadcasts and television broadcasts because they can be created by alternating current and can cause an alternating current in metals.
Dangers
- There are no dangers of radiowaves.