 Review Sheet Lenses

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 Resource lessons: Refraction Converging Lenses Diverging Lenses Thin Lens Equation Double Lens Systems Lens-Maker Equation, Power, Combinations Ray Diagram Labs: Converging Lenses (6 cases) Diverging Lenses (2 cases) Worksheets: Thin Lens Equation #1 Thin Lens Equation #2 Thin Lens Equation #3 Thin Lens Equation #4 Thin Lens Equation #5 Converging Lens Vocabulary Diverging Lens Vocabulary CP Workbook:  Lens Review Lens-Maker Equation
 Thin lenses - devices which refract light converging lenses in air (chart) thicker in the center than on the edges, convex converge light - principal focus is to the right usually form real inverted images (review 6 cases) (#6) form enlarged virtual upright images when do < f (#5) do not form any image when do = f (parallel rays) (#4) form real enlarged images when 2f < do < f (#3) form real images that are the same size as the object when do = 2f (#2) form real reduced images when do > 2f (#1) form point images when do Ţ Ą diverging lenses in air (chart) thicker on the edges than in the center, concave diverge light - principal focus is to the left always form reduced virtual upright images thin lens equation do is always positive with a single lens di is positive for real images, negative for virtual images f is positive for converging lenses, negative for diverging lenses magnification thin lenses in close combination power of a lens measured in Diopters focal length must be measured in meters Lens-maker's equation  n1 is the index of the lens n2 is the index of the surrounding medium r1 is the radius of curvature for the front surface (+ if convex, - if concave) r2 is the radius of curvature for the back surface (+ if convex, - if concave) Kshape represents the shape of the lens which does not change when placed in different mediums double-lens systems when drawing ray diagrams or using the thin-lens equation, work each lens separately remember that the image of lens #1 is the object for lens #2 to calculate do for lens #2, subtract di for lens #1 from the total distance separating the lenses the magnifications of the system is the product of the magnifications of each separate lens  converging/converging and converging/diverging systems converging/converging can form a final image that is either real and upright or virtual and inverted converging/diverging form virtual inverted images ray diagram for microscope - virtual image formed by eyepiece Refraction index of refraction c = 3 x 108 m/sec n > 1 the index is a measure of a medium's optical density (photon interaction with electrons) dispersion:  a medium's index of refraction is actually frequency dependent (spectrum) Snell's Law  light bends towards the normal when it enters a more dense medium light slows down when its travels through a more dense medium the wavelength of light decreases as it travels through a more optically dense medium the frequency of light is an invariant - it never changes

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