Image Characteristics
Worksheet Answers
State the four LAST characteristics of an image in a plane mirror.
Location
The
object
is actually
the same
Place where
light rays
cross or
appear to cross.
distance to the mirror as
the image is to the
mirror.
Attitude/
Orientation
The image is upright.
Size
The image is the same
size as the object.
Type
real: light
rays actually
in front of mirror
The
image
iscross
reversed
virtual: light rays appear to cross behind mirror
compared to the object.
4. Define the following optical terms.
Angle of Incidence (i)
angle between the incident ray and the normal
Angle of Reflection (r)
angle between the reflected ray and the normal
Incident Ray
Normal
Reflected Ray
incoming light ray
dashed line drawn perpendicular to the mirror at the point
of reflection
light ray reflected from the mirror
2. What does virtual image mean?
A virtual image is the image of an object in a mirror.
3. Relate each letter in the diagram to one of the following
optical terms
c)
d)
e)
b)
f)
angle of incidence (i)
normal
angle of reflection (r)
incident ray
reflected ray
d)
b)
f)
c) e)
g)
a)
h)
5. State the Laws of Reflection from a plane mirror.
- The angle of incidence is equal to the
angle of reflection.
- The incident ray, the normal, and the
reflected ray all lie on the same plane.
6. Does a candle have to be in front of a mirror in order
to form an image? Try It!
Both candles can form images. The “mirror” must be extended
to find the location of the image for candle #2.
It is there, but how must you look?
Measure the distance from the top of the object to
the mirror (dO).
Copy this distance (dOtop) to the other side of the
mirror. It becomes (dItop).
Repeat this process for the bottom of the object.
These two points give the location of the top and
bottom of the image. For any point dO = dI.
Rays of light must be entering the eye as if they
had come straight from the image.
That is the way the eye sees things.
The line is dotted behind the mirror because light rays
cannot go through an opaque mirror.
They travel in this direction but could not have come
from the image’s location.
The light rays that appear to come from the top
of the image really came from the top of the
object and reflect off the mirror into the eye.
The light rays that appear to come from the
bottom of the image really came from the bottom
of the object and reflect off the mirror into the
eye.
Your Turn
Complete question #8
A) should look like this.
B) should look like this.
C) should look like this.
D) should look like this.
9. Which Eye-Brains can see the image #1?
Image #1
10.Which Eye-Brains can see image #2 in the mirror?
Image #2
11. Show where the Images are located
…………
12. Which Eye-Brain can see
ii) Image of candle #2
A, B, C, D?
A, B, C, D?
13. What determines whether an Eye-Brain observer can see an image or not?
There must be straight line connecting eye to the image.
14.Use the laws of reflection to show how the eye-brain
sees the top and bottom of a candle in a periscope.
Roughly parallel rays from the top and bottom of
the candle move towards the top mirror.
Angle of Incidence = Angle of Reflection (i = r )
the rays move towards the bottom mirror
Angle of Incidence = Angle of Reflection (i = r )
and the rays move towards the Eye-Brain mirror.
The candle’s image appears erect or upright.
15.Use the laws of reflection to show how the eye-brain
sees the top and bottom of a candle if the top mirror is
be rotated to face backwards?
Roughly parallel rays from the top and bottom of
the candle move towards the top mirror.
Angle of Incidence = Angle of Reflection (i = r )
rays move towards the bottom mirror
Angle of Incidence = Angle of Reflection (i = r )
and the rays move towards the Eye-Brain.
The candle’s image appears inverted.
16. How do Bicycle Reflectors Work?
Why not just use a mirror to reflect light back into the
Eye-Brain?
Because slight changes in the mirror’s orientation would
cause the reflected light to miss the Eye-Brain.
If two mirrors are arranged at 90º, ......
If two mirrors are arranged at 90º, slight changes in
the mirrors’ orientation do not affect the general
direction of the reflected light.
The incident ray hitting a reflector is sent back in the same direction