| • Light consists of that area of the electromagnetic spectrum that
contains wavelengths that can be detected by the human eye. |
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• Know the parts of the EM spectrum (see chart in text)
• In a vacuum, light (and all EM waves) travels at 300,000,000 m/sec.
• Brightness decreases by the square of the distance from the source.
• Reflection is a change in the direction of light.
• Specular reflection is in one direction only (ex. mirror).
• Diffuse reflection doesn't produce a clear image.
• The incidence angle and reflected angle are equal.
• A flat mirror forms a virtual image
behind the mirror. |
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• Image location can be predicted with ray diagrams.
• Concave mirrors focus light to form real images in front of the mirror.
• Depending on their location, the image can be larger or smaller than
the object.
• Real images can appear in front of a concave mirror.
• Mirror equation: 1/p + 1/q = 1/f
p = object distance
q = image distance
f = focal length
• f=R/2 (R is the radius of curvature)
• Magnification = h'/h
h' = image height
h = object height |
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• To construct a ray diagram for a concave mirror:
For a particular point on the object,
Parallel rays bounce back through the focal point
Rays through the focal point bounce back parallel
Rays through the center of curvature bounce straight back
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• Convex mirrors produce a smaller virtual image. |
• Spherical mirrors produce some blurriness known as spherical aberration.
• Parabolic mirrors eliminate spherical aberration.
• Reflecting telescopes use parabolic mirrors.
• Color is perceived when only some wavelengths of light are reflected
• White - the reflection of all wavelengths of light; none is absorbed
• Black - the absorption of all wavelengths of light; none is reflected
| • Primary light colors - red, blue, green
• Complementary light colors – a primary and the color formed from mixing
the other 2 primaries; when complementary lights are combined, they produce
white light |
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• Primary pigment (primary subtractive)
colors- yellow, cyan, magenta |
• Polarization - results in light that travels in one plane only
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