week 9

• Reflection of light


  The abrupt change in the direction of propagation of a wave that strikes the boundary between two different media
• Reflection of light


  • At least some part of the incoming wave remains in the same medium
  • Occurs when light bounces off an object
  • Happens when a light beam strikes any polished, smooth, or bright surface and bounces back
• Law of reflection


  • The angle of incidence (θi) is equal to the angle of reflection (θr)
  • The incident ray, the reflected ray and the normal to the mirror at the point of incidence all lie in the same plane
• Types of reflection


  • Specular / Regular
  • Diffused / Irregular
• Specular / Regular reflection


  Occurs at smooth, plane boundaries and the light get reflected in the same medium forming image of the object
• Diffused / Irregular reflection


  • Occurs at rough, irregular boundaries
  • The light bounces back in all directions giving rise to general illumination
  • Helps us to see things
• Mirror left-right reversal


  • A phenomenon observed when looking at a reflection in a flat mirror
  • A type of reflection where the image appears reversed from left to right
  • The left side of the object appears as the right side of the image and the right side appears as the left
  • Explains why the word "AMBULANCE" in an ambulance car is flipped
• Spherical mirrors


  • Concave mirrors
  • Convex mirrors
• Concave mirrors


  A curved mirror in which the reflective surface BULGES AWAY from the light source
• Convex mirrors


  • The reflective surface BULGES TOWARDS the light source
  • Reflect light outwards
• Refraction of light


  The bending of light as it moves from one medium to another
• Optical density


  A measure of a substance's ability to transmit electromagnetic radiation
• Index of refraction


  The ratio of the speed of light in a vacuum to the speed of light in a particular medium
• Snell's law


  The angle of refraction depends on the speed of light in the two media and on the incident angle