Combined P4

• Waves are vibration of particles that transfer energy
• Radio longest wavelength lowest frequency
• Gamma rays highest frequency shortest wavelength
• Uv

  X Ray

  Gamma rays

  Can cause cancer
• Half live is the time taken for activity to halve
• Mechanical waves Need a medium to travel
• Electromagnetic waves

  Don't need a medium Travel at same speed Speed is 3x10^8
• Speed of wave

  Frequency x wavelength
• Longitudinal waves

  Vibrate at 90 degrees

  Example sound
• Time period

  T=1/f

  Time taken to complete one wave
• Spectrum

  R radio waves

  M micro

  I infrared

  V visible light

  U ultra violet

  X x rays

  G gamma rays
• Properties of emw

  Transverse waves

  Transfer energy

  Travel at 3x10^8

  Can travel through a vaccum
• Gamma radiation

  Electromagnetic wave

  Stopped by lead
• Beta raditation

  Fast moving electron

  Stopped by allumminium

  Electron emitted

  Add 1 to smaller no
• Alpha raditation

  Helium atom

  Stopped by paper

  4 mass no.

  2 atomic no.

  Minus a he atom ( -4 and -2)