1. Reflection Physics Department, New York City College of Technology

2. Key words Reflection The law of reflection Plane mirror Concave mirror Convex mirror Mirror equation Ray tracing diagram

3. Law of reflection The incident and reflected rays lie in the same plane with the normal to the surface The angle of reflection equals the angle of incidence ii rr Incident light ray Reflected light ray Normal to surface Angle of incidence Angle of reflection

4. Reflection/refraction from plastic block Disc 22 #6

5. Image formed by a plane mirror D o is object distance D i is image distance For a plane mirror D o =D i

6. Spherical mirrors convex Concave Ray diagram principal axis focal point focal length radius of curvature

7. Image formed by a spherical mirror Three special rays Ray 1: P ray Ray 2: F ray Ray 3: O ray

8. Mirror equation Making use of geometry we can prove Magnification

9. Mirror equation (continued) The sign conventions: h o : + h i : + for upright image,  for inverted image d i /d o ; + if in front of the mirror,  if behind the mirror f: + for concave mirror,  for convex mirror

10. Example #1 Spherical mirror