Images in Plane Mirrors
Remember this?
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Virtual Image
• Appears to be a
light source behind
the mirror
• This is an apparent
light source
• Light can’t travel
through mirror, so
vase is a virtual
(reflected) image
Virtual Image
source
mirror
apparent
source
Locating an Image
• We can use light rays and the Law
of Reflection to show where plane
mirrors produce a virtual image
• distance from object to mirror is the
same as from the mirror to image
• The object-image line is
perpendicular to the mirror
• Let’s take a look…
Locating an Image
Objectimage line
object
normals
image
Try one yourself!
Pick an object point
Now draw in the
light rays and
find the image!
Pick a view point
Lateral Inversion
• Let’s look at words in a plane
mirror! Write your name in block
letters and hold it up to the mirror
• What do you see?
• What would this image look like?
Z
Lateral Inversion
• In a plane mirror, each letter is
flipped horizontally and the letters
are in reverse order.
• This property is called lateral
inversion …but why would anybody
use this?
Image Characteristics
• Use the acronym “SALT” to examine
properties of an image:
S – Size of Image(compared to object –
larger, smaller or same size)
A – Attitude of Image (upright or inverted)
L – Location of Image
T – Type of Image (real or virtual)
Images in Plane Mirrors
• Compared to the object, an image
in a plane mirror is always:
S – the same size
A – laterally inverted
L – behind the mirror (same distance
as object is to the mirror)
T - virtual
Activity
• In your lab group, work on
Investigation 11.8 on Pg. 494
And/or
• Hmwk. Pg. 493 #1-5,7,9,10