chap 11 electromagnetic spectrum

• what type of waves are electromagnetic waves ?

  transverse waves
• what are the components of em waves from lowest to highest frequency ?

  1. radio
  2. microwave
  3. infrared
  4. visible
  5. ultraviolet
  6. x-ray
  7. gamma ray
• what are the characteristics of em waves ?

  1. transverse waves
  2. consist of magnetic and electric fields that oscillate 90 ° to each other
  3. transfer energy from one place to another
  4. travel through vacuum
  5. same speed of 3.0 x 10^8 m/s in vacuum
  6. obey the laws of reflection and refraction
  7. carry no electric charge
• what is the wavelength of radio waves ?

  10 ^3
• what is the wavelength of microwaves ?

  10^-2
• what is the wavelength of infrared waves ?

  10 ^-5
• what is the wavelength of visible waves ?

  10 ^-6
• what is the wavelength of ultraviolet waves ?

  10 ^-8
• what is the wavelength of x-ray waves ?

  10 ^-10
• what is the wavelength of gamma rays ?

  10 ^-12
• what are the properties of radiowaves ?

  • very long wavelengths
  • produced by making electrons oscilliate in an antenna
  • used to transmit video and audio information over long distances
• what are the applications of radio waves ?

  • communication by police, ship pilots
  • AM and FM radio broadcasting
  • remote control toys
  • over- the air TV
  • radar systems
• what are the properties of microwaves ?

  • produced by electronic circuits in devices
  • used in 5G networks
  • can penetrate food and cause water molecules to vibrate vigorously, generating heat to cook the food
  • reflected by metals
• what are the applications of microwaves ?

  • microwave oven
  • wifi
  • global positioning system (GPS)
  • satellite communication
  • satellite TV
• what are the properties of infrared radiation ?


  • produced by any bodies with temperature above 0K
  • detected by thermopile, phototransistor or thermometer
• what are the applications of infrared radiation ?

  • infrared thermal scanner
  • infrared motion sensor
  • infrared map for pain relief therapy
  • remote control
  • ear thermometers
• what are the properties of visible light ?

  • made up of seven components of coloured lights
  • detected by the human eye and photographic film
  • used for vision
• what are the applications of visible light ?

  • transmit information in optical fibres for use in telecommunication
  • endoscopy
• what are the applications of ultraviolet radiation ?

  • forgery detection
  • water purification
  • sunbed for artificial tanning
  • sterilise medical equipment
  • disinfect rooms
• what are properties of x-rays ?

  • can pass through paper, thing sheets of metal and flesh
  • can damage cells
  • can penetrate all types of metal except for lead
• what are the applications of x-rays ?


  • airport security in x-ray machines
  • radiography to scan for bone fractures
• what are applications of gamma rays ?

  • treatment of cancers
  • feed irradiation to extend the shelf life of foods by reducing or elimination bacteria in the food
  • gamma radiography to detect damage, corrosion, wall thickness and welding imperfections on field and piping welds