Optics

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Optics
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The Deviation of Light Waves

• Light propagates rectilinearly (in a straight
  line)
• when the substance it travels through allows
  it
• Some objects are visible because they emit their
  own light, they are luminous.
• Others are visible only because some light rays
  bounce off their surface towards our eyes
• This phenomenon is called reflection.

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Reflection

• What allows us to see two balloons?

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Reflection

• Some light rays are emitted in all directions

And allow us to see the object directly
Surface or the water
Other light rays bounce back the surface of the
water, allowing us to see an inverted copy of the
object
Thus the illusion of another object in the water
the VIRTUAL IMAGE
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Reflection
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Reflection
?i
?r
Angle of incidence
Angle of reflection
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Optic Fibers

• Optic fibers are designed to reflect light
  throughout their entire length, thus emitting an
  ultrafast, low-temperature and very accurate
  signal

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The Deviation of Light Waves

• Sometimes, when light travels from one substance
  to another with a different density, part of the
  light rays are deviated without being reflected
• This phenomenon is called refraction.

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• For example, if a light ray travels from air to
  water (liquid), it penetrates another substance
  with a different density
• Examples of light refracting materials are water,
  glass, plastic, diamonds and oils

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REFRACTION

• Normal

Normal
?i
?r1
Incident Ray
Reflected Ray
Glass
The refracted ray is deviated toward the normal,
since the light ray travels from less dense to
denser matter
Refracted Ray
?r2
Angle of Refraction
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REFRACTION
Normal
Normal
This time, the refracted ray is deviated away
from the normal, since the light ray travels from
denser to less dense matter
?r2
Angle of Refraction
Refracted Ray
Glass
Incident Ray
Reflected Ray
?i
?r1
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REFRACTION
Real fish, actual position
Virtual fish, illusory position
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Uh?

• Archer fish are better than the best baseball
  players at predicting where plummeting prey will
  land, suggests a new study. They need only one
  glance although their eyes see their prey at a
  refracted angle.
• The fish (Toxotes jaculatrix) shoot water jets
  from their mouths at insects perched overhead.
• After a hit, they have to guess where their lunch
  will land, and get to it before it's gobbled by
  fellow fish.

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Lenses

• There a 2 type of lenses
• Convergent lenses
• Divergent lenses

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Convergent Lenses

• Biconvex lens

Planoconvex lens
Convergent meniscus
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Convergent Lenses
Incoming light rays
Focal Point
Optical axis of the lens
Refracted light rays
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Convergent Lenses

• The light rays converge to a specific point on
  the axis of the lens.
• This point is called the focal point, and its
  location on the axis is determined by the
  curvature of the lens.
• The more pronounced the curve of the convergent
  lens, the closer to the lens the focal point is.

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Convergent Lenses

• Example of a more pronounced curve

Focal Point
Optical axis of the lens
Refracted light rays
Incoming light rays
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Convergent Lenses

• This is not exactly true though
• In reality Biconvex lens create a double
  refraction of the light rays, like so

Focal Point
Incoming light rays
Refracted light rays
Optical axis of the lens
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Divergent Lenses
Biconcave lens
Planoconcave lens
Convexo-concave lens
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Divergent Lenses
Incoming light rays
Optical axis of the lens
Refracted light rays
Focal Point
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Divergent Lenses

• This time, the light rays are deviated away from
  the axis.
• The focal point is found by extending the
  refracted rays until they meet
• This point of origin of the refracted rays is the
  Focal Point
• The focal point is now on the same side as the
  incoming rays of light

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How it works
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How it works
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So overall
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End