Reference Tools & Resources
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Chapter 26: Reflection, Refraction and Geometrical Optics Reference Tools & Resources |
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Reference Tools & Resources
I. Key Terms and Phrases
geometrical optics: the study of the reflection and refraction of light under the ray approximation.
light ray: a representation of the straight-line propagation of light.
law of reflection: the fact that the angle of incidence equals the angle of reflection for light reflecting from a smooth surface.
object: the source of light from which an image will be formed by a mirror or a lens.
image: the representation of an object resulting from the convergence, or apparent convergence, of light rays coming from the object by reflection or refraction.
upright image: right-side-up with respect to the object.
inverted image: upside-down with respect to the object.
magnification: ratio of the image height to the object height.
focal point: the point on the principal axis at which incident rays that are parallel to the principal axis (or their extensions) will intersect after reflection or refraction.
real image: an image formed by the intersection of light rays.
virtual image: an image formed by the intersection of extensions of light rays into a region where no light is actually present.
refraction: the phenomenon that the direction of propagation of light generally changes when it crosses the boundary between two media.
index of refraction: the ratio of the speed of light in a vacuum to the speed of light in a medium.
Snell's law: relates the angle of incidence to the angle of refraction.
total internal reflection: occurs at incidence to the angle of refraction.
Brewster's angle: the angle at which refracted light is completely polarized.
dispersion: the spreading of light of different frequencies due to the fact that the index of refraction is frequency dependent.
II. Important Equations
| Name/Topic | Equation | Explanation |
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| The law of reflection. | ||
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The mirror equation. | |
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This expression for the magnification applies to both mirrors and lenses. | |
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The definition of the index of refraction. | |
| Snell's law which describes the refraction of light. | ||
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The thin lens equation. |
III. Know Your Units
| Quantity | Dimension | SI Unit |
|---|---|---|
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