P3/4 - Waves, light and the Electromagnetic Spectrum

• What do waves transfer?

  Energy and information
• What do waves NOT transfer?

  Matter
• Define frequency?

  Number of vibrations (or number of waves) per second, measured in hertz (Hz)
• Define wavelength?

  The shortest distance between a point on a wave and the same point on the next wave, measured in metres (m)
• What is a longitudinal wave?

  A wave where the vibrations are PARALLEL to the direction in which the wave is travelling
• What is a transverse wave?

  A wave where the vibrations are PERPENDICULAR to the direction in which the wave is travelling
• What is refraction?

  The change in direction when a wave goes from one medium to another
• What type of wave are ALL electromagnetic waves and what speed do they travel in a vacuum?

  Transverse, the same speed
• What are the seven main groupings of the continuous electromagnetic spectrum (in order)?

  Radio waves

  Microwaves

  Infrared

  Visible light (ROYGBIV)

  Ultraviolet

  X-rays

  Gamma rays
• List the electromagnetic spectrum in order of increasing wavelength?

  Gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves, radio waves
• List the electromagnetic spectrum in order of increasing frequency/energy?

  Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.
• What is a harmful effect on people of excessive exposure to microwaves?

  Internal heating of body cells
• What is a harmful effect on people of excessive exposure to infrared?


  Skin burns
• What is a harmful effect on people of excessive exposure to ultraviolet?

  Damage to surface cells and eyes -> leading to skin cancer and eye conditions
• What is a harmful effect on people of excessive exposure to x-rays and gamma rays?

  Mutation of damage to cells in the body
• Describe uses of microwaves?

  Cooking, Mobile phone, satellite communications
• Describe some uses of infrared?

  Cooking, thermal imaging, TV remote
• Describe some uses of UV?

  Security marking, disinfecting water, detecting forged bank notes
• Describe some uses of x-rays?


  Medical diagnosis, security scanners