Curved Mirrors

• • Concave (converging) mirror: the centre of the mirror bends away from you. “Caves in” the inner surface is reflective 
  • Car headlights, flashlights, TV satellite dishes, shaving and makeup mirror, inside of spoon
• • Convex (diverging) mirror: centre of mirror bends out towards you. Outer surface is reflective
  • Side view mirrors and security mirrors
• Centre of Curvature ©: centre of a sphere 
• Vertex (V): the centre of the curved mirror (point where the principle axis meets the mirror)
• Principal Axis (PA): line going through the centre the centre of curvature and the vertex (this line joins the centre of curvature with the vertex)
• Converge: to meet at a common point. The point where the reflected rays meet represents the top part of the image being created
• Focus or Focal point(F): the point on the principal axis where rays meet when incident rays that run parallel to the PA are reflected off a concave mirror
• Rule 1: an incident ray is drawn parallel to the principal axis and the reflected ray runs through the focus

  Rule 2: an incident ray is drawn through the focus and the reflected rays runs parallel to the PA

  Rule 3: an incident ray is drawn through the C and the reflected ray will reflect back onto itself
• Convex Mirrors 

  • Focal point and centre of curvature are always on opposite sides of the mirror as the object for convex mirrors
  • Light rays appear to come from a light source behind the mirror
  • Image will always be virtual

  1. S - smaller
  2. A - upright
  3. L - Behind mirror, closer to mirror than object
  4. T - Virtual 
• Differences  

  • ‘F’ is called virtual focus (reflected rays are extended behind the mirror and meet at a point on the principal axis)
  • ‘F’ and ‘ C’ are located behind the mirror (comes from a light source away from the mirror)

  Rule 1: draw a ray parallel to the principal axis that is reflected as if it had come through the virtual focus, extend w/ dotted line

  Rule 2: ray directed toward the virtual focus is reflected parallel to the principal axis

  Rule 3: ray aimed at the centre of curvature is reflected upon itself