Refraction

• What is the phenomenon called when light waves change direction as they pass from one medium to another?

  Refraction
• Why do waves travel at different speeds in different materials?

  Because different materials have different densities
• How does the density of a medium affect the speed of electromagnetic waves like light?


  The higher the density, the slower the wave travels through it
• What happens to a light wave when it travels from air into glass?


  It slows down and bends towards the normal
• What is the normal line in the context of refraction?


  It is the dashed line perpendicular to the surface at the point of incidence
• What occurs when a light wave hits the boundary at an angle?

  It will be refracted, changing its direction
• How do you draw a proper ray diagram for refraction through a piece of glass?


  1. Draw the normal line at the point of incidence.
  2. Draw the incident ray towards the glass.
  3. Draw the refracted ray bending towards the normal.
  4. Continue the refracted ray to the other side of the glass.
  5. Draw the normal again at the exit point.
  6. Draw the emergent ray bending away from the normal.
  7. Label the angles of incidence and refraction.
• What happens to the speed of a wave when it passes from a more dense medium to a less dense medium?


  It speeds up and bends away from the normal
• What does the wave speed equation state?


  Wave speed equals frequency times wavelength
• What remains constant when a wave changes medium?

  The frequency of the wave
• What happens to the wavelength of a wave if its speed increases?


  The wavelength must also increase
• What is the result of passing white light through a triangular prism?


  It spreads out into a spectrum of colors
• what are light waves


  they are transverse waves that can be reflected and refracted
• How does white light behave when passed through a triangular prism?

  • Different wavelengths of light are refracted by different amounts.
  • This causes the colours to spread out like a rainbow.
  • Red is refracted the least
  • Purple is refracted the most

  
• If light hits a boundary at 90 degrees to the surface, will the light refract?

  No it will not
• How does light travel in a triangular prism?

  When light passes from air to the glass of the prism, the change in speed causes the light to change direction and bend

  
• What happens when light is refracted while passing through 2 different media?

  The light changes speed and direction in the new medium

  If the new medium is more dense, the light will travel slower and bend towards the normal

  If the new medium is less dense, the light will travel faster and bend away from the normal
• What happens when light enters a more optically dense medium?

  When light enters a more optically dense medium, the angle of incidence (the angle between the

  incident ray and the normal) is greater than the angle of refraction (the angle between the refracted ray and the normal). 

  The opposite is true when light enters a less optically dense medium.