../ Refraction is the bending of a wave front as the wave front passes between two substances in which the speed of the wave differs ../ The angle of refraction 8r is the angle between the refracted ray and normal line ../ Refraction occurs when light's velocity changes ../ When light moves from one medium to another, part of it is reflected and part is refracted; the frequency of the light does not change during refraction ../ When the light ray moves from air into glass, the refracted ray is bent toward the normal; when the light ray moves from glass to air is bent away from the normal ../ The index of refraction is the ratio of the speed of light in a vacuum to the speed of light in a given transparent medium; indices of refraction are in the reference table ../ If the light moves from medium 1 to medium 2., Snell's law determines the angle of refraction 82: nlsin81 = n2sin82 ../ A lens is a transparent object that refracts light rays such that they converge or diverge to create and image ../ When rays of light pass through a converging lens (thicker at the middle), they are bent inward; when they pass through a diverging lens (thicker at the edge), they are bent outward ../ Farsightedness can be corrected with converging lenses; nearsightedness can be corrected with diverging lenses ../ The total internal reflection is the complete reflection that takes place within a substance when the angle of incidence of light striking the surface boundary is greater than the critical angle ../ The critical angle is the angle of incidence at which the refracted light makes an angle of 90° with the normal ./ Total internal reflection occurs only when the light moves from a medium with higher index of reaction to one medium with lower index of refraction ../ Mirage is produced by the bending of light rays in the atmosphere when there are large temperature difference between the ground and the air

1. Which band of the electromagnetic spectrum has: a. the lowest frequency?

b. the shortest wavelength?

2. Suppose an intelligent society capable of receiving and transmitting radio signals lives on a planet orbiting Procyon, a star 95 light-year away from Earth. If ~ signal were sent toward Procyon in 1999, what is the earliest year that Earth could expect to receive a return message?

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a concrete driveway d~ftl4. Set'1 an undisturbed pond spec4'~rl~ a polished silver tray s-pecl.4lo.v-I'f a sheet of paper d~ttlA.S~ l~ a projection screen in a movie theater

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4. If you are stranded on an island, where would you align mirror to use sunlight to signal a searching aircraft?

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14. Glycerine is used to make soap and other personal care products. Find the critical angle for light traveling from glycerine (n=1.473) into water (n=1.333).

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16. The diagram shows a light ray (5.09 x 1014 Hz) in air, incident on a boundary with fused quartz. At the boundary, part of the light is refracted and part of the light is reflected.

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a. Using a protractor, measure the angle of incidence of the light ray at the airfused quartz boundary. ~\So b. Calculate the angle of refraction of the incident light ray. 0 • V\,~~.,e,":: V\t. S"~V\e1. \.sl\"i15":: 1.46$(,"192 c. Using a protractor and straightedge, construct the refracted light ray in the fused quartz on the diagram.

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