Evans SPH 3U1

Physics Grade 11

Unit 3: Light and Optics

Note 2: Reflection and Plane Mirrors


Reference: Chapter 10.4


Wavefronts and Wave Rays

Normal - reference line perpendicular to a surface

Incident Ray and Reflected Ray



- angle of incidence is equal to the angle of reflection.. Angles are drawn between the normal and incident or reflected ray.



Real Image - can be captured on a screen (i.e. pinhole camera)

Virtual Image - cannot be captured on a screen (i.e. mirrors)


Drawing Ray Diagrams for a Plane Mirror:

1) Draw a reference line (normal) half way between the object and the viewing eye

2) Draw at least two light rays to get a reasonable image

        i)    and ii)

3) Extend the rays behind the mirror.

For plane mirror reflections

- the image appears behind the mirror.

- the image is reversed (lateral inversion) but right side up

- the same size as the object


Complete 14-2 Handout

Review Questions page 345 # 4, 6, 16, 19, 25ac, 29, 33, 38, 40