Specular reflection occurs off smooth surfaces at defined angles, while diffuse reflection scatters light in many directions from rough surfaces. The law of reflection states that the angle of incidence equals the angle of reflection. A flat mirror produces virtual images through reflection, where the image is reversed from the object.

1. Reflection of
Light 13.2
Karla Mendez and Shelby Bowen

2. Introduction
•
In this lesson we are going to talk about
what reflection is and the difference
between specular and diffuse reflection of
light. We will also be applying the law of
reflection for flat mirrors and explain and
describe images formed by flat mirrors.

3. Key Words
•
•
•
•
Reflection
Angle of incidence
Angle of reflection
Virtual image

4. Specular Reflection
•
•
Specular reflection is defined as light
reflected from a smooth surface at a
defined angle.
This is an example of specular reflection.

5. Diffuse Reflection
•
•
•
Diffuse reflection is reflection off of rough
surfaces such as clothing, paper, and the
asphalt roadway.
Diffuse reflection originates from a
combination of internal scattering of light.
Diffuse reflection allows us to see most
things around us.
o
Example: Light is diffusely reflected from a paper in
many directions.

6. Diffuse Reflection
•
You can see that the the reflection of the
light hitting the rough surface causes
it to scatter in
many different
directions.

7. What is the Law
of Reflection (flat mirrors)?
• Reflection is when a ray of light strikes a
•
•
•
plane mirror, the light ray reflects off the
mirror.
Flat mirrors are the simplest form of a
mirrors
Reflection is a change in direction of the
light ray.
The law states that the angle of incidence
is equal to the angle of reflection.

8. Key words on the
Law of Reflection
•
•
•
•
•
Angle of incidence
Angle of reflection
Incident ray
Reflection ray
“Normal”

10. What is the angle
of incidence?
•
•
Angle of incidence is the angle between a
beam incident on a surface and the
normal.
Line perpendicular to the surface at the
point of incidence.

11. ●
● The red line
represents the
incident ray
(sunlight)
● The black line
represents the
normal
● The angle
between the two
is called the
angle of
incidence

12. What is the angle
of reflection?
•
•
•
The angle between a reflected ray and the
normal, drawn at the point of incidence to a
reflecting surface.
Light reflects off a mirror at the same angle
as it did when it (incident ray) hit the mirror.
A mirror can only reflect 90% of incident
light.

13. The distance between
the normal (dotted line)
and the reflected ray
(red line) is the angle of
reflection.

14. Images formed by flat
mirrors
-Whats an image?
❖A real image of an object produces the
same pattern of light as the object does
somewhere in space.
❖A virtual image is the apparent position
from which a pattern of light reaches our
detector, if we make the assumption that it
has traveled from its source to the detector
along a straight-line path.

15. Virtual
The reason
why the
virtual image
looks lighter
is because
only 90% of
the original
image is
being
reflected by
the mirror.
Real image

16. What’s in the
mirror?
•
•
When you look in the mirror you are looking
at a reversed you!
The image of your left is now on the right
and your right is on the left.
o
Example: When you are brushing your teeth and you
have a shirt on the says Hollister, in the mirror it will
be backwards because a mirror reverses the virtual
image (image in the mirror) from the original (real
image).

17. The baby’s reflection is
reversed. You can see that the
baby’s right side of its body is
reflected on the left and the left
is on the right

18. Images Formed by flat
mirrors continued..
•
•
•
Mirrors can produce real and virtual
images by reflection.
A flat mirror only produces virtual images.
The Law of Specular Reflection states that
light reflecting from a plane mirror forms an
angle to the NORMAL equal to the angle
between the normal and the incident light.

19. Summary
● Specular reflection is defined as light
reflected from a smooth surface at a
defined angle.
● Diffuse reflection is reflection off of rough
surfaces
○ clothing, paper, asphalt roadway
○ scattering of light
○ allows us to see most things

20. Summary
(Continued)
•
Reflection is when a ray of light strikes a
plane mirror
o
•
o
flat mirrors are the simplest form of mirrors
reflection is a change of reflection in a light ray
The law of Reflection states that the angle
of incidence is equal to the angle of
reflection

21. Summary
(Continued)
•
•
Angle of incidence is the angle between a
beam incident on a surface and the
normal.
The angle between a reflected ray and the
normal, drawn at the point of incidence to a
reflecting surface.

22. Summary
(Continued)
•
•
A real image of an object produces the
same pattern of light as the object does
somewhere in space.
o
Example: You
A virtual image is the apparent position
from which a pattern of light reaches our
detector
o
Example: Your reflection in the mirror

23. Summary
(Continued)
•
•
Mirrors can produce real and virtual
images by reflection.
A flat mirror only produces virtual images.
o
Example: The mirror in your bathroom

24. Questions?

25. Bibliography
All Things Reflected. (n.d.). Optics For Kids. Retrieved October 25, 2013,
from http://www.optics4kids.org/home/teachersparents/articles/thereflection-of-light/
Molecular Expressions Microscopy Primer: Light and Color - Reflection of
Light: Interactive Java Tutorial. (1998, June 21). Molecular Expressions
Microscopy Primer: Light and Color - Reflection of Light: Interactive Java
Tutorial. Retrieved October 25, 2013, from
http://micro.magnet.fsu.edu/primer/java/reflection
Reflection of light. (2012, April 18). Science Learning Hub RSS. Retrieved
October 25, 2013, from http://www.sciencelearn.org.nz/Contexts/Light-andSight/Science-Ideas-and-Concepts/Reflection-of-light