Ch. 18 Mirrors and Lenses

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Ch. 18Mirrors and Lenses

• Milbank High School

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Sec. 18.1Mirrors

• Objectives
• Explain how concave, convex, and plane mirrors
  form images.
• Locate images using ray diagrams, and calculate
  image location and size using equations.
• Explain the cause of spherical aberration and how
  the effect may be overcome.
• Describe uses of parabolic mirrors.

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Plane Mirrors

• Plane mirrors
• Object
• Images
• Virtual Image

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Concave Mirrors

• Reflects light from its inner caved in surface
• Principal axis
• Focal point
• Focal Length
• Real Images

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Concave Mirrors

• Real, inverted images if object is farther from
  the mirror than the focal point

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Calculations
di is distance from the image to the mirror d0 is
the distance from the object to the mirror f is
focal length of the mirror

• Lens/Mirror Equation
• Magnification
• Example problem Pg. 422
• Calculating the Real Image Formed by a Concave
  Mirror
• Example problem Pg. 424
• A Concave Mirror as a Magnifier

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Convex Mirrors

• Reflects light from its outer surface, always
  diverge
• No real image, upright
• Reduced in size (wide angle mirrors)

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Calculations

• Use same Lens/Mirror Equation
• Focal length is negative
• di is negative (image is behind the mirror)
• Pg. 427 Pr. 6

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Sec. 18.2Lenses

• Objectives
• Describe how real and virtual images are formed
  by convex and concave lenses.
• Locate the image with a ray diagram and find the
  image location and size using a mathematical
  model.
• Define chromatic aberration and explain how it
  can be reduced.
• Explain how optical instruments such as
  microscopes and telescopes work.

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Types of Lenses

• Lens
• Convex lens
• Concave lens

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Convex lenses (converging lenses)

• Produce real, inverted images if the object is
  farther from the lens than the focal point
• If object is closer than the focal point, a
  virtual, upright, enlarged image is formed

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Concave Lenses (diverging lenses)

• Produce virtual, upright, reduced images

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Calculations

• f is positive for convex lenses
• f is negative for concave lenses
• do is positive on the object side of the lens
• di is positive on the other side (image side) of
  the lens, where images are real
• di is negative on the object side of the lens
  where images are virtual
• Ex. Prob. Pg 431
• Ex Prob. 434