waves

• whats the value for the speed of sound?

  340m/s
• in longitudinal waves, what hqppens to the vibrations?

  parallel to the direction of wave travel
• what are 3 examples of longitudinal waves?

  • sound waves
  • ultrasound
  • seismic p-waves
• what do longitudinal waves show areas of?

  compression and refraction
• what do compressions show regions of?

  high pressure due to particles being close together
• what do refractions show regions of?

  low pressure due to particles being spread further apart
• the energy and oscillations in a longitudinal wave are?

  parallel
• in transverse waves, the vibrations are in a what?

  perpendicular to the direction of wave travel
• what are 3 examples of transverse waves?

  • electromagnetic waves
  • ripples on the surface of water
  • seismic S-waves
• the energy and the oscillations in a transverse wave are what?

  perpendicular to each other
• where do waves travel in the electromagnetic spectrum?

  the same speed through a vacuum or the air
•  What do electromagnetic waves transfer?

  energy
•  What is the average speed electromagnetic waves travel at through a vacuum?

  300 million metres per second
• What do electromagnetic waves form?

  A continuous spectrum of waves
• What are the seven distinct groups in this spectrum of electromagnetic waves?

  • Gamma rays
  • X-rays
  • ultraviolet
  • visible light
  • infrared
  • microwaves
  • radio waves
• What frequency, wavelength, and energy do gamma rays have?

  • High frequency
  • short wavelength
  • high energy
• What wavelength, frequency, and energy do radio waves have?

  • Long wave length
  • low frequency
  • low energy
• What is the frequency of each group in the electromagnetic wave spectrum?

  They range
• What are radio waves used for?

  Communication such as radio
• How are radio waves transmitted?

  Easily through the air
• What happens to the human body with radio waves?

  Do not cause damage if they are absorbed and can be reflected to change their direction
• What are radio waves produced by?

  Oscillations in electrical circuits
• When radio waves are absorbed by a conductor what do they create?

    An alternating current
• What are microwaves used for?

  Cooking food and satellite Communications
• What causes the heating for microwaves?

  The internal energy of the molecules increase when they absorb microwaves
• How are microwaves absorbed by the food?

    Frequencies are easily absorbed by molecules in the food
• What makes microwaves good for satellite Communications?

  They can pass easily through the atmosphere
• What is infrared used for?

  • Electrical heaters
  • cookers for cooking food
  • infrared cameras
• What is infrared absorbed by?

  Chemical bonds
• What causes the heating in infrared?

  The internal energy of the bonds increase when they absorb infrared light
• Can humans see infrared light?

  No
• What is thermal imaging useful for by using infrared?

  For detecting people in the dark
• What is visible light?

  The light which we can see
• What is visible light used in?

  Fibre optic Communications
• What effect does ultraviolet have on the human body and what is the problem?

  Can have hazardous effects but we can't see ultraviolet light
• Where is ultraviolet light typically found in nature?

  Sunlight
• What is ultraviolet used for?

    Fluorescent substances are used in energy efficient lamps
• How do electromagnetic waves help medicine?

  • X-rays are absorbed by dense structures like bones which helps to identify broken bones
  • high energy waves are transmitted through soft body tissues with very little absorption making them ideal for internal imaging
  • gamma rays are produced by changes in the nucleus of an atom which is a form of nuclear radiation
• What are three types of ionizing radiation from the electromagnetic spectrum?

  • Ultraviolet waves
  • X-rays
  • gamma rays
• How does ionization have hazardous effects on the body

  • ultraviolet waves can cause skin to age pre maturely and increase the risk of skin cancer
  • x-rays and gamma rays can cause the mutation of genes which can lead to cancer