EM spectrum - Physics

• Em waves have different wavelengths and different properties. They are grouped into seven types depending on their wavelengths.
• radio waves

  microwaves

  infrared

  visible light

  ultra violet

  x-rays

  gamma rays
• radio waves have the lowest frequency and the longest wavelength

  gamma rays have the highest frequency and shortest wavelength
• All types of EM radiation are tranverse wavesd and travel at the same speed through a vacuum
• EM waves can be reflected, refracted or absorbed by matter they pass through
• radio waves are used mainly for communications

  microwaves are used for satellite communication and heating food

  Infrared radiation is used for heating and to monitor temperatures

  Light signals can travel through optic fibres

  visible light is useful for photography

  Ultra violet is used in fluorescent lamps (UV)

  x-rays let us see inside things like the body

  gamma radiation can be very useful for sterilising medical equipment and food
• Microwaves can heat human body tissue - they need shielding to prevent this

  Infrared can burn human skin - protect your skin by using insulating materials

  UV radiation can damage surface cells and cause blindness - use suncream and sun glasses

  gamma rays can cause cell mutation or destruction leading to tissue damage or cancer - medical treatment