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Engineering optics
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the study of how light interacts with matter
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Luminous Flux
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the measure of the total amount of energy radiated per second from a light source in all directions (measured in lumens (lm)
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Illumination
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a measure of the light that falls on a surface (measured in lux (lx))
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Illumination Formula
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E = P/4πr2 (E = illumination, P = luminous flux, r = distance)
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Diffraction
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the spreading of waves around barriers
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polarization
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the restriction of light to one direction
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Primary colours
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RGB
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concave
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depends on position
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convex
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virtual, upright, smaller
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concave properties
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infinitely large
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real, inverted, highly diminished at focus
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at focus
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real, inverted, infinitely enlarged (no image)
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beyond focal point
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virtual, erect, enlarged image
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2x the focal length
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real, inverted, same size
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before focal point = inverted and smaller
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after focal point = erect and larger
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virtual images cannot be collected on screen
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convex lens
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collects light
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concave lens
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scatters light
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Magnification
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the ratio of the image's length to the object's length
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Magnification formula
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M = hi / ho or -di / do ( M is -ive if its real )
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1/f = 1/di + 1/do
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interference
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when two waves superimpose to form a wave with a higher or lower amplitude
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young's double slit experiment
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explains interference; uses monochromatic light to create dark and light bands
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λ = xd/L
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Reflection Law
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incident angle = reflected angle
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Properties of a plane image
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1- virtual
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2- upright
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3- same size
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4- horizontally inverted
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5- same distance
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concave mirror
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collects light rays (used in telescope)
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convex mirror
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scatters light rays (sides of cars)
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Principal Axes
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center line
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Focus / focal point
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the point at which light rays appear to converge
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Focal Length
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the distance between the center of the mirror and the focus
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focal length formula
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f = r/2 (r = radius of curvature)
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Refraction
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the bending of light through a medium
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snell's law
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n1sinθ1 = n2sinθ2 (n is the refractive index)
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refraction index
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n = c/v (c is the speed of light, v is the speed of light in the medium)
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complete reflection
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reflection within a medium that occurs when the angle of incidence is greater than the critical angle
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critical angle
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the angle of incidence that causes the reflected angle to have 90 degrees
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complete reflection applications
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optical fibers
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mirage
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an optical illusion caused by a difference in temperature that creates refraction
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rainbow
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when light is scattered by water droplets
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farsightedness (long focal length)
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corrected with a convex lens
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nearsightedness (image forms in front of retina)
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corrected with concave lens
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
