Applications of EM Waves (Edexcel IGCSE Science (Double Award): Physics): Revision Note

Applications of EM waves

• Each region of the electromagnetic spectrum has a variety of uses and applications

Uses of EM waves

Radio waves & microwaves

• Both radio waves and microwaves are used in wireless communication

• This includes:

  • Radios

  • Air traffic communication

  • Mobile phone communication

• At very high intensities microwaves are used to heat things in a microwave oven

Infrared

• Infrared is emitted by warm objects and can be detected using special cameras (thermal imaging cameras).

• Examples of the uses of infrared are:

  • Security cameras to see people in the dark

  • TV remote controls

  • Transport signals through fibre optic cables

Visible

• Visible light is the only part of the electromagnetic spectrum that the human eye can see

• It is used in photography, where light is focused onto a sensor or film to produce an image

Ultraviolet

• Ultraviolet is responsible for giving you a sun tan, which is your body’s way of protecting itself against the ultraviolet rays

• When certain substances are exposed to ultraviolet light, they absorb it and re-emit it as visible light (making them glow)

  • This process is known as fluorescence

• Fluorescence can be used to secretly mark things in special ink, such as banknotes

X-rays

• The most obvious use of X-rays is in medicine

• X-rays can pass through most body tissues but are absorbed by the denser parts of the body, such as bones

Gamma Rays

• Gamma rays are dangerous and can be used to kill cells and living tissue

• Gamma rays can also be used to sterilise equipment by killing off the bacteria