Light and Its Uses

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Light and Its Uses
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Reflection of Light

• specular (regular) reflection
• all light rays that hit a smooth surface are
  reflected at the same angle
• diffuse reflection
• reflected light is scattered in many directions
  due to a rough surface

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Mirrors

• Plane (flat) mirrors
• flat surface
• left and right are reversed
• give a virtual image
• the image you see is where you think the light
  came from, not where it actually came from

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• concave mirrors
• mirror curves inward
• help to concentrate light on a spot called the
  focal point

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• convex mirrors
• mirror surface curves outward
• the focal point is behind the mirror
• used in automobile rear-view mirrors
• objects appear farther than they really are

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concave mirror
convex mirror
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Color

• the color of an object is determined what
  color(s) of light are reflected
• example a red object looks red because red light
  is reflected

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Refraction of Light

• white light is made up of all the visible colors
  (ROYGBIV)
• each color (wavelength) of light is refracted
  (bent) a different amount
• prisms can separate white light into its colors
  (called dispersion)
• red, with the longest wavelength, bends the least
• violet, with the shortest wavelength, bends the
  most

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• may make objects appear to be in different
  positions

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A Rainbow
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Lenses

• transparent material that bends light to create
  an image
• converging lens
• magnifying glass
• diverging lens
• viewfinders in cameras

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