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Section 7: Rays and waves. Exercise answers. Paragraph 1. a. light bulb, LED light, the Sun b. table, wall, dirt, the Moon It is impossible to look in a curve Light beams never bend Laser pointers always point straight forward a. it will be reflected b. it will be absorbed
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Section 7: Rays and waves Exercise answers
Paragraph 1 • a. light bulb, LED light, the Sunb. table, wall, dirt, the Moon • It is impossible to look in a curveLight beams never bendLaser pointers always point straight forward • a. it will be reflectedb. it will be absorbed • a. t = 384 000km ÷ 300000km/s = 1.28sb. t = 150 000 000km ÷ 300000km/s = 500s • Red light waves are longer than violet light waves. • Light of a single wavelength and therefore a single colour.
Paragraph 2 • a/b. see imagec. virtual imaged. No, the light line from the tail does not pass the mirror(see the red dashed line) • Current distance to image: 10m + 10m = 20mDistance to mirror needed: 5m ÷ 2 = 2.5mDistance to be walked: 10m – 2.5m = 7.5m
Paragraph 3 • On the whiteboard
Paragraph 4 air glass ∠i • a. see imageb. the refraction will be less, so the angle of refraction will be larger. • a. dispersionb. violet lightc. red light ∠refr. normal
Paragraph 7 • a. A b. Ac. The point where all light rays hitting the lens perpendicularly converged. Distance from the lens to the principal focus • a. Close to the lensb. It will move away from the lens and get larger • object distance = image distanceobject height = image height