Unit 8 Objectives: Light and Optics
8.1
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8.2
Light and Matter
Describe the ray model of light
Define luminous intensity, luminous flux, and illuminance
Know the symbols and names for luminous intensity, luminous flux, and illuminance, and their units,
solve problems relating them.
Explain the formation of color by light and by pigments or dyes
Describe the nature of polarized light
Identify the 3 primary colors of light and the 3 secondary colors of light
State the effect of mixing two primary colors of light
Define complementary colors and state the effect of mixing two complementary colors of light
Optics
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Explain the laws of reflection and refraction
Distinguish between diffuse and regular reflection and provide examples
Calculate the index of refraction in a medium
Distinguish between incident and refracted rays.
Define and distinguish between the normal, the angle of incidence and the angle of refraction.
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Explain how concave, convex, and plane mirrors form images.
Distinguish between concave and convex mirrors
Use Ray Diagrams to locate images produced by concave or convex mirrors.
Use Ray Diagrams to determine whether the images produced by concave or convex mirrors are
inverted or erect, enlarged or reduced, and real or virtual.
Use the Lens/Mirror Equation to determine whether the images produced by concave or convex
mirrors are inverted or erect, enlarged or reduced, and real or virtual.
Use the Lens/Mirror Equation to determine whether images produced by concave or convex mirrors
are inverted or erect, enlarged or reduced, and real or virtual.
Explain the cause of spherical aberration and how the effect may be overcome.
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Explain how lenses form real and virtual images.
Distinguish between convex (converging ) and concave (diverging) lenses
Use Ray Diagrams to locate images produced by concave or convex lenses.
Use Ray Diagrams to determine whether the images produced by concave or convex lenses are
inverted or erect, enlarged or reduced, and real or virtual.
Use the Lens/Mirror Equation to determine whether the images produced by concave or convex
lenses are inverted or erect, enlarged or reduced, and real or virtual.
Use the Lens/Mirror Equation to determine whether images produced by concave or convex lenses
are inverted or erect, enlarged or reduced, and real or virtual.
Define chromatic aberration and explain how the effect may be reduced.
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f
do di
Lens/Mirror Equation:
Magnification Equation:
hi  d i
M 
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ho
do
Rules for Drawing Ray Diagrams:
All Rays are drawn from the top point of the object.
Draw Ray 1: Ray 1 is directed parallel to the principal axis.
Mirrors:
Ray 1 is reflected through the focal point f.
Convex Lenses:
Ray 1 emerges from the lens directed towards focal point f1
Concave Lenses:
Ray 1 emerges from the lens directed away from focal point f
Draw Ray 2: Ray 2 is directed in line with point f. (except in concave lenses)
Mirrors:
Ray 2 is reflected parallel to the principal axis.
Convex Lenses:
Ray 2 emerges from the lens parallel to the principal axis.
Concave Lenses:
Ray 2 is directed in line with point f1
and emerges parallel to the principal axis.
Draw Ray 3: Ray 3 is directed towards the center of the mirror or lens.
Mirrors:
Ray 3 is reflected as in a plane mirror. (<incidence = <reflection)
Lens:
Ray 3 emerges from the lens with no change in direction.
Draw the Image:
rays meet.
The image’s top point will be where the all three reflected or transmitted
Note: If the reflected/transmitted rays do not meet, trace them backwards to their apparent
origin, to see where they converge to form a virtual image. When “backtracing”, use a dotted line
to show that these are apparent rays, not actual light rays. Note that in these cases, the image is a
virtual image, not a real image. If none of the rays converge at all, then no image will be formed.