Reflections and Images in Curved Mirrors.docx

  • Reflections and Images in Curved Mirrors
  • Learning Expectation(s): A1.12, E2.1, E2.2, E2.3, E3.3
  • Curved Mirror Terminology
  • curved mirror: curved reflective surface
  • concave: inside surface of a sphere
  • convex: outside surface of a sphere
  • centre of curvature (C): centre point of sphere
  • vertex (V): point at the middle of mirror
  • principle axis (PA): line connecting C and V
  • focal point (F): point on PA that is half-way between C and V
  • focal length (f): distance between V and F
  • radius of curvature (2f): distance between V and C
  • Concave Mirror
  • Convex Mirror
  • Concave Mirror
  • Convex Mirror
  • Using Ray Diagrams to Find Images - Convex
  • use 3 rays which touch the object:
  • 1 incident ray parallel to PA – extension of reflected ray will pass through F
  • 1 incident ray towards F – reflects parallel to PA
  • 1 incident ray to V – reflects according to law of reflection
  • image will be located where reflected rays appear to intersect
  • Qualitative Image Characteristics
  • Concave Mirror
  • Convex Mirror
  • always the same
  • S – smaller
  • A – same
  • L – behind mirror, closer to mirror
  • T – virtual
  • Using Ray Diagrams to Find Images - Concave
  • use 3 rays which touch the object:
  • 1 incident ray parallel to PA – reflects through F
  • 1 incident ray through F – reflects parallel to PA OR
  • 1 incident ray through C – reflects on itself
  • 1 incident ray to V – reflects according to law of reflection
  • image will be located where reflected rays (appear to) intersect
  • Qualitative Image Characteristics
  • Concave Mirror
  • depend on location of object
  • S – same, larger, or smaller
  • A – same or inverted vertically
  • L – in front or behind; same distance, closer or further
  • T – real or virtual
  • sometimes no image is generated
  • Convex Mirror
  • always the same
  • S – smaller
  • A – same
  • L – behind mirror, closer to mirror
  • T – virtual