Reflection and refraction

Reflection and refraction are important in communications signals.

Reflection

Wireless signals can be reflected off buildings and other large objects. This means that signals may be received even if the receiver is not in direct sight of the transmitter. But it can also cause ‘ghosting’ on television pictures, for example.

Reflection is also important in wired communications. An optical fibre is a thin rod of high-quality glass that absorbs very little light. Even when the fibre is bent, light getting in at one end undergoes repeated total internal reflection and emerges at the other end.

Optical fibre

Refraction

Radio waves are refracted by different layers in the Earth’s atmosphere. This leads to a reduction in the signal, making it difficult for them to be received over long distances. Unlike radio waves, microwaves are not refracted, so they are used for satellite communications.

Microwaves and radio waves in the atmosphere

Now try a Test Bite