Reflection + refraction

• The normal line (imaginary) is at 90 degrees to the mirror; allows us to take measurments, but cannot otherwise. First thing to do when drawing reflection diagram
• Angle i = angle of incidence
• angle r = angle of reflection
• Law of reflection = angle i + angle r = equal
• ALL WAVES REFLECT
•  λ stays the same after reflection

  F stays the same after reflection

  V stays the same after reflection

  nothing changes, wave stays the same, only change = direction
• This is a refraction diagram

  A) Normal line

  B) Normal line

  C) light

  D) incident ray

  E) reflected ray

  F) emergent ray

  
• Refraction = wave changes direction because it enters a different material, slowing down; when it exits it speeds up

  A) enters, slows down

  B) exits, speeds up

  
• entry angle (should) = exit angle
• Refraction:

  • F stays the same -> never changes
  • shorter  λ inside, but same when it exits (to measure  λ, measure from peak to peak)
  • V= shorter inside glass
• refraction = a wave moves from one material to another and changes direction, because the wave changes speed (loses speed in the different material)
• label

  A) Normal line

  B) angle of incidence

  C) angle of reflection

  D) Incident ray

  E) Reflected ray

  F) mirror