Waves

• What are the two types of waves?

  Transverse and longitudinal.
• What are transverse waves?

  Waves that oscillate perpendicular to the direction of energy transfer.
• What are examples of transverse waves?

  Ripples on the surface of water

  Vibrations on a guitar string

  Electromagnetic waves

  S-waves
• True or False: Transverse waves can travel in solids, surfaces of liquids, and vacuums

  True
• true or false: Transverse waves transfer energy but not the particles of the medium.

  True.
• What are longitudinal waves?

  Waves that oscillate parallel to the direction of energy transfer.
• What is the highest point above the rest position called?

  Peak/ Crest
• What is the lowest point below the rest position called?

  Trough.
• What do we call it when particles in a longitudinal wave are close together?

  Compressions.
• What do we call it when particles in a longitudinal wave are far apart ?

  rarefaction.
• Give examples of longitudinal waves.

  Sound waves

  P-waves

  Pressure waves
• In what medium do transverse waves travel fastest?

  in vacuums
• In what medium do longitudinal waves travel fastest?

  Solids.
• What are waves?


  They are oscillations about a fixed point. They transfer energy and information but not matter.
• What is amplitude?

  The maximum displacement moved by a wave from its rest position.
• What is the unit for amplitude?

  metres.
• What is wavelength?


  It is the distance travelled by a wave in one time period
• What is the unit for wavelength?

  metres.
• What is frequency?


  The number of waves made in one time period. It is measured in Hertz (Hz).
• What is time period?


  The time needed to make one complete wave.
• What is the equation for wave speed?

  Wave speed = frequency x wavelength
• What is the unit for wave speed?

  m/s
• Give the equation relating frequency and time period.

  f= 1/T
• What is the doppler effect?


  The apparent change in frequency and wavelength caused by the relative movement of the source of waves or the observer.
• Give properties of electromagnetic waves.

  They are all transverse waves

  They travel at the speed of light

  They can travel through a vacuum
• What is the relationship between wavelength and frequency?

  They are inversely proportional.
• What is the only wave from the EM spectrum which can be seen by humans?

  Visible light.
• Give uses of infrared radiation.

  remote controls

  Infrared cookers and heaters

  night vision

  thermal imaging
• Give uses of UV radiation

  Tanning

  Fluorescent tubes
• Give uses of X-rays.


  taking images of human bones

  Airport security
• Give uses of gamma rays

  treating cancer (radiotherapy)

  Sterilising equipment and food
• What are the risks of UV radiation.

  severe eye damage

  skin cancer

  Sun burn
• What are the risks of microwaves?

  Internal heating of body tissue which can cause organ damage.
• Why are microwave ovens safe and do not harm humans?

  They have metal walls and metal grids which prevent microwaves from escaping
• What are the risks of x - rays and gamma rays?

  Internal damage to organs

  Can lead to cancer
• What safety measures are taken to prevent the risks of x- rays and gamma rays?

  using lead boxes

  wearing lead aprons (wearing protective equipment)
• What are the risks of infrared radiation?

  Skin burns
• What can light undergo?

  Reflection and refraction
• True or False: All waves in the Electromagnetic spectrum can be reflected and refracted.

  true.
• What are the two types of objects?

  Luminous and non-luminous objects.