1) The use of total internal 'reflection' of light is to a. shape diamonds b. straighten mirrors c. check the surface of glass d. check the density of liquids
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2) The critical angle for glass is a. 40 degree b. 41 degree c. 42 degree d. 43 degree
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3) Yellow lights stimulate a. red and blue cones b. red and green rods c. red and green cones d. red and blue rods
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4) Each ray of light is a. reflected in the droplet b. refracted in the droplet c. dispersed in the droplet d. converted to other forms of light in the droplet
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5) If a ray of light enters the surface of diamond at an angle of 24 Degree or more, the light would a. end b. reflect back c. refract at a greater angle d. totally internally reflect
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6) The higher the "refractive index" a. the less the light bends b. the more the light bends c. the more the light speeds up d. the less the light slows down
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7) A line drawn at right angle to the plane is known as a. critical angle b. critical plane c. perpendicular plane d. normal
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8) In optical fiber, the data is transferred in form of a. sound b. vacuum c. light d. heat
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9) The number of the most common shapes of lenses are a. 1 b. 2 c. 3 d. 4
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10) An example of object that uses concave lenses, is a. contact lenses b. telescope c. spectacles d. microscope
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11) The lens in our eye can change its thickness due to a. muscles connection b. brain power c. will power d. living cells
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12) The number of cone cells in an eye is a. 2 million b. 4 million c. 6 million d. 8 million
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13) We can see things because they a. absorb light b. reflect light c. create light d. stimulate the photons of light
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14) We see different colors on screen because dots change their a. colors b. brightness c. sharpness d. size
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15) The critical angle is basically the a. angle of incidence b. angle of refraction c. angle of reflection d. angle of rarefaction
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16) For long-sightedness, the lenses that are used, are a. convex b. concave c. biconcave d. flat lenses
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17) Converging means to a. spread out b. invert c. bring together d. shrink
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18) A color filter removes a. bright colors b. dull colors c. unwanted colors d. wanted colors
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19) Light travels in a. vacuum only b. curled lines c. straight lines d. air only
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20) When light enters water from air, its speed decreases to a. 20,000 km/s b. 25,000 km/s c. 200,000 km/s d. 250,000 km/s
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21) The lenses work due to the a. reflection of light b. refraction of light c. rarefaction of light d. all of them
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22) Diverging means to a. spread out b. invert c. bring together d. magnify
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23) An example of luminous objects is a. Moon b. Earth c. Sun d. Wall
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24) When light travels through a transparent object, it a. reflects b. refracts c. speeds up d. changes color
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25) Our brain mixes the colors by a. mixing the rods b. mixing the cones c. combining the signals from rods d. combining the signals from cones
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26) The color that is not part of the spectrum is a. blue b. brown c. indigo d. violet
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27) When light enters a denser medium, it bends a. away from the normal b. towards the normal c. away from the plane d. towards the plane
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28) Objects that let some light to pass through are known as a. transparent objects b. opaque objects c. translucent objects d. half transparent objects
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