Plane Mirror Notes

Mirrors and

images

Poll

How often do we Pass mirrors in a given day?

• 10

• 30

• 5

• 60

Reflection

• The change in direction of a wave hitting a

reflective surface.

• The wave returns back into the same medium.

Plane Mirror Reflection

•Mirror:

• A mirror is a reflective surface that light does not
pass through.

• I.e. No transmission of light
• Possibly a very small amount of absorption, but will be

ignored.

Plane Mirror Reflection

Incident Ray

(1) Incident Ray

• Ray of light travelling towards and hitting the

mirror.

Plane Mirror Reflection

Incident Ray

Normal

(2) Normal

• An imaginary reference line, perpendicular,

or at a right angle, to the surface of the
mirror.

Plane Mirror Reflection

Incident Ray

Normal

Reflected Ray

(3) Reflected Ray

• Ray of light travelling away and reflected

from the mirror.

Plane Mirror Reflection

Incident Ray

Normal

Reflected Ray

Angle of Incidence

(4) Angle of Incidence

• The angle between the incident ray and the

normal.

Plane Mirror Reflection

Incident Ray

Normal

Reflected Ray

Angle of Incidence

Angle of Reflection

(5) Angle of Reflection

• The angle between the reflected ray and the

normal.

Plane Mirror Reflection

Incident Ray

Normal

Reflected Ray

Angle of Incidence

Angle of Reflection

Virtual Image

(6) Virtual Image

• An image positioned as far behind the mirror

as the real object is in front of the mirror

• Created from incident light rays that have

reflected of an object in front of the mirror.

Multiple Choice

Assuming the real person is on the right and is standing 3 feet away from the mirror how far are they from their virtual image?

• 2 feet

• 3 feet

• 4 feet

• 6 feet