em waves

• What phenomenon is demonstrated when light appears to change direction passing through water?

  Refraction
• What causes waves to change direction?

  Changing speed when moving between mediums
• In a ray diagram, what happens to light's velocity when it passes from air into glass?

  Velocity decreases, light waves slow down
• When waves slow down, how do they bend in relation to the normal?

  They bend towards the normal
• How is the normal line drawn in relation to the surface of the glass?

  At right angles to the surface
• What happens to the velocity of light waves when they pass from glass back into air?

  Velocity increases, waves speed up
• When waves speed up, how do they bend in relation to the normal?

  They bend away from the normal
• What happens to the image of an object due to refraction?

  It appears to have shifted position
• When does refraction occur?

  When a wave changes speed between mediums
• Under what condition do waves not change direction when entering a new medium?

  If they enter along the normal
• What is a wavefront?

  Imaginary line connecting same points in waves
• What points on a set of waves can a wavefront connect?

  Same points in a set of waves
• What does showing wavefronts instead of wave diagrams allow you to visualise?

  Lots of waves moving together
• What happens to parts of the wavefront when they start to move into glass?

  Those parts of the wavefront slow down
• As wavefronts enter glass, what happens to the wavelength?

  Wavelength gets smaller
• What causes the waves to change direction towards the normal?

  The wavelength gets smaller
• What happens to the wave fronts when approaching along the normal?

  The waves slow down as they pass
• What happens if the whole wavefront slows down at the same time?

  The waves do not change direction
• How do wavefront diagrams help explain refraction for higher tier students?

  Visualizing speed changes across a wavefront
• What happens when white light passes through a prism?

  It splits into a spectrum
• What type of waves are electromagnetic waves?

  Transverse waves
• What do electromagnetic waves do?

  Transfer energy from source to absorber
• In a microwave oven, what acts as the source of energy?

  The oven
• In a microwave oven, what acts as the absorber of energy?

  The food
• What happens when white light is passed through a prism?

  It splits into a spectrum
• What varies between each color of light in a spectrum?

  Wavelength and frequency
• On the red end of the visible light spectrum, how are the waves characterized?

  Lower frequency and longer wavelength
• On the violet end of the visible light spectrum, how are the waves characterized?

  Higher frequency and shorter wavelength
• Is visible light a large or small part of the electromagnetic spectrum?

  Small part
• What part of the electromagnetic spectrum can be detected by the human eye?

  Visible light
• What are the different waves in the electromagnetic spectrum?

  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet light
  • X-rays
  • Gamma rays
• As you move from radio waves to gamma rays, what happens to the frequency?

  The frequency increases
• As you move from radio waves to gamma rays, what happens to the wavelength?

  The wavelength decreases
• What is meant when scientists say the electromagnetic spectrum is continuous?

  Cutoff point between waves isn't always clear
• Do electromagnetic waves need a medium to travel in?

  No
• What does it mean that electromagnetic waves don't need a medium to travel in?

  They can travel through a vacuum
• What is the speed of all electromagnetic waves in a vacuum?

  3 x 10^8 meters per second
• What do different materials do to electromagnetic waves?

  Absorb, transmit, or reflect them
• What does how a material interacts with electromagnetic waves depend on?

  The wavelength
• What type of materials are microwaves absorbed by?

  Foods containing water molecules