Physics of Light

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Physics of Light
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Light

• Electromagnetic wave
• Needs NO medium to travel
• Transverse wave.
• Speed of Light 3.00 x 108 m/s
• (In air and in a Vacuum)

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Speed of Light

• ALL electromagnetic waves travel at the speed of
  light
• (Radio, TV, Gamma, Ultraviolet and Infrared. . .
  See Reference Table)

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Dual Nature of Light

• Light sometimes behaves like a particle
• Light sometimes behaves like a wave

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White Light

• The light that comes from the sun and other
  artificial means is called white light or visible
  light.
• White Light is composed of the colors of the
  rainbow.

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Visible Light

• ROY G. BIV

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Light Energy

• Luminous Objects Objects that generate their
  own light
• Illuminated Objects Objects that are capable of
  reflected light

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Light Reflection

• Regular Reflection

• Diffuse Reflection

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Refraction of Light
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Refraction of Light

• Speed of light is dependent on the medium it is
  traveling through
• Optical density (How well light can pass through)

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Index of Refraction

• Index of Refraction Number that tells how
  optically dense an object is based on the speed
  of light through it.

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Index of Refraction Value

• Ratio of the speed of light in a vacuum to the
  speed of light in the material.
• n index of refraction
• c speed of light (m/s)
• v velocity (m/s)

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Snells Law

• As light speeds up, it bends AWAY from the normal
• As light slows down, it bends TOWARDS the normal

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• Using Snells Law and the values for n in the
  diagram below, draw arrows to show the path
  through the layers of different materials.

Air (1.0)
Flint Glass (1.61)
Water (1.33)
Diamond (2.42)
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Diffraction

• Bending of a wave around an obstacle
• Single Slit Diffraction

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Diffraction

• Double Slit Diffraction

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Diffraction

• Size of opening and wavelength affect the
  diffraction pattern
• Greatest diffraction pattern occurs with a long
  wavelength and narrow opening

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Polarization

• Unpolarized light Light waves which are
  vibrating in more than one plane (Sun, lamps,
  candle)
• Polarized Light Light waves in which the
  vibrations occur in a single plane

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Polarization

• Polarization process of transforming
  unpolarized light into polarized light.
• Uses - Sunglasses

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WARM-UP

• The speed of light in Lucite is _________?
• The speed of light in goop is 2.56x108 m/s. What
  is the index of refraction of goop?

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Lab 17 and 18

• Lab 17
• Problem How are the angle of incidence and the
  angle of reflection related?
• Lab 18
• Problem How are the angle of incidence and the
  angle of refraction related?