Uses of Electromagnetic Waves

What are radio waves used for?

Radio broadcasting and television transmission.

Why are radio waves suitable for broadcasting?

They can carry information over long distances and be detected by aerials.

What are microwaves used for?

Satellite communications and cooking food.

Why are microwaves suitable for satellite communications?

They can pass through the atmosphere and carry information to and from satellites.

Why are microwaves used in microwave ovens?

They are absorbed by food, transferring energy and heating it.

What are infrared waves used for?

Electrical heaters, cooking food and thermal imaging cameras.

Why is infrared radiation useful in electrical heaters?

It is absorbed by objects, transferring energy to their thermal stores.

Why are infrared cameras useful?

They detect infrared radiation emitted by objects, allowing temperature differences to be observed.

What is visible light used for in communications?

Fibre-optic communication.

Why is visible light suitable for fibre-optic communication?

Light pulses can carry information through optical fibres.

What are ultraviolet waves used for?

Energy-efficient lamps and fluorescent materials.

Why is ultraviolet radiation useful in fluorescent lamps?

It causes fluorescent coatings to emit visible light.

What are X-rays used for?

Medical imaging, particularly of bones.

Why are X-rays useful for imaging bones?

Bone absorbs more X-rays than soft tissue, creating image contrast.

What are gamma rays used for?

Cancer treatment and some medical imaging techniques.

Why can gamma rays be used to treat cancer?

Their ionising effects can damage or destroy cancer cells.

Why can different electromagnetic waves be used for different purposes?

Their wavelengths, frequencies and interactions with materials differ.

Why are some electromagnetic waves more suitable for communication than others?

Their ability to travel through materials, be transmitted and be detected differs.

Why are infrared cameras useful in darkness?

They detect infrared radiation rather than relying on reflected visible light.

Why can visible light travel along an optical fibre?

Light can undergo total internal reflection within the fibre.

What is total internal reflection?

When light is completely reflected inside a material at a boundary, under suitable conditions.