Waves

• What is the purpose of radio waves

  To transfer information and used used for communication
• What are the three waves to do with Radio Waves

  Short Waves

  Long Waves

  Very short waves
• What are features short waves

  Over long distances

  Reflect over the Ionosphere ( The electrical charged layer of the atmosphere ). They bounce up and down making it easier to travel over long distances
• What are features of Long Waves

  Over huge distances like from London to China

  It is over a huge distance because they bend around the Earth‘s surface
• Some microwaves can be absorbed water molecules and some cannot
• What happens in Microwave ovens with water molecules ?

  They absorb energy of the Microwaves

  Then water molecules start vibrating and transfer energy to neighbouring molecules
• What type Of objects are Infrared Radiation emitted by

  Objects with thermal energy
• What is visible light

  Light we use to see
• Does visible light have several colours

  Yes basically the colours of the rainbow ( DONT SAY THIS IN YOUR EXAM)
• How can Visible light be used to transfer energy

  It can use what we call Optical Fibres such as glass or plastic
• What Optical Fibres do with Visible Light

  They reflect it as it goes through and it helps transfer information over long distances
• What should Optical Fibres not do with Visible Light

  Absorb it
• What is an alternative way of transferring Visible Light for sending information ?

  Copper wires ( Electricity )
• What are the disadvantages of Copper Wire with Visible light ?

  Problems with Signal

  It does transfer as much information
• Where does UV Light comes from?

  The Sun
• What does Florescence do?

  Absorbs Ultraviolet light then energy is re- emitted as Visible light
• Uses of Ultraviolet light

  Can sterilise water as it can destroy microorganisms

  Can be used for security eg. Seeing if someone is faking a passport