Reflection of Light

• Reflection - Bouncing back of light into the same medium it has been traveling after striking a surface
• Incident Ray - Ray that strikes through a surface
• Reflected Ray -Ray that rebounds from the surface
• Normal - Line perpendicular to the surface
• Law of Reflection - The angle of incidence is equal to the angle of reflection
• What are the two types of reflection?

  Regular and Diffuse
• Regular - Reflection from smooth surfaces. Reflected rays are parallel
• Diffuse - Reflection from rough surfaces. Reflected rays are scattered and not parallel
• Mirrors - Any surface that is smooth enough to produce a regular reflection of light incident upon it
• What are the types of mirrors?

  Plane and Spherical Mirrors
• Plane Mirror - is a type of mirror with a flat surface
• Spherical Mirror - has a reflecting surface taken from surface of sphere
• Plane mirrors are used by Architects
• What are the types of spherical mirrors?

  Concave and Convex
• Concave - Curves inward in the direction of incident rays
• Convex - Curves outward to the direction of incident rays
• What are the two types of Plane mirror images?

  Real and Virtual Images
• Real Images

  • Formed by actual intersection of reflected rays 
  • Formed in front of mirror and is always upside down
• Virtual Images

  • Formed behind the mirror and upright relative to object 
  • No actual intersection of incident rays
• Center of Curvature (C) - The center of the sphere where the mirror is taken
• Vertex (V) - Center of the mirror. Also called the pole of mirror
• Radius of Curvature (R) - Radius of the sphere. Distance between C and V
• Principal Axis - Also called Optical Axis, the straight line joining C and V
• Aperture (AB) - Refers to the width of the mirror
• Principal Focus (F) - Point where reflected rays meet (most important point)
• Focal Length (f) - Distance from Vertex to Principal Focus
• Concave - Converging Mirror
• Convex - Diverging Mirror
• Concave Mirror 

  • Produces real or virtual images, depending on the distance between mirror and object 
  • Produces either bigger or smaller images
• Convex Mirror 

  • Produces virtual image only since reflected rays spread out
  • Images are always upright, and smaller that the object
• Ray Tracing 1  - A ray passing through the center of curvature is reflected along itself
• Ray Tracing 2 - A ray parallel to optical axis is reflected through the focus
• Ray Tracing 3 - A ray passing through the focus is reflected parallel to the optical axis
• Ray Tracing 4 - A ray striking the vertex is reflected at an equal angle on the opposite side of the optical axis
• f = Focal Length
• R = Radius of Curvature
• do = Object distance from vertex
• di = Image distance from vertex
• M = Magnification
• M = >1 - The image is magnified