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Ray Diagram Quiz
•
•
object
2F
F
principal axis
concave
State the characteristics
of the mirror
image:
S:
P:
O:
T:
object
•
F
principal axis
State the characteristics of the
image:
S:
P:
O:
T:
• http://www.youtube.com/watch?v=zNqXtz
TcIqE
• http://www.physicsclassroom.com/class/refl
n/u13l3e.cfm
Refraction of Light
What is Refraction?
• Refraction: The bending of light as it
travels from one material to another.
• Light waves travel faster in air than through
other substances (water, glass, etc). As
light rays pass
• Refraction:
• http://www.brainpop.com/science/energy/re
fractionanddiffraction/
Why Does Light Refract?
• The speed of light differs in different
transparent materials.
• The denser the material the slower light
travels as it passes through.
• As light travels from air into denser water, it
slows down.
• The change of speed causes the light to
change direction.
Why Refraction is Important
• Your eyes depend on refraction!
• When you read, the light reflects off of the
page, travels towards your eyes and refracts
when it enters the lens of each eye.
Lenses
• Lens: A curved transparent device that
causes light to refract as it passes through.
• There are 2 types of lenses:
– Concave Lenses
– Convex Lenses
Lenses
The first telescope, designed and built by Galileo, used lenses to focus light from
faraway objects, into Galileo’s eye. His telescope consisted of a concave lens and a
convex lens.
light from
object
convex
lens
concave
lens
Light rays are always refracted (bent) towards the thickest part of the lens.
Concave Lenses
•
F
principal axis
Light rays that come in parallel to the principal axis still diverge from the focal point.
Convex Lenses
•
F
principal axis
Light rays that come in parallel to the principal axis converge at the focal point.
Questions:
1.
2.
3.
a)
Explain why light bends as it travels from air into water.
Light refracts more when passing from air to diamonds
that any other common material. What can we conclude
about the speed of light in a diamond?
Determine which way light will bend and draw the
refracted ray. Explain.
air
water
b)
air
water
air