Module # 15 Light
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15.1 Which of the pictures below is the best illustration of the quantum-mechanical theory of light?
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b.
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15.2 Suppose a particle is traveling through air at 250,000,000 meters per second. If the particle suddenly hits a lake, what will happen to its speed?
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The particle's speed will drop.
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2. Explain the wave theory of light, the particle theory of light, and the quantum-mechanical theory of light.
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The wave theory of light is that light is a wave that travels through electrical field and the magnetic field. The particle theory of light is that light is made up of tiny particles that can't be seen. The quantum-mechanical theory of light is that light is tiny packets of wave called photons. Not a continuous wave but broken up.
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3. Sound waves cause air to oscillate. What do light waves oscillate?
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They oscillate the electrical field and the magnetic field.
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4. What does Einstein's Special Theory of Relativity say about the speed of light?
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It says that nothing can travel faster then the speed of light in any given substance.
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5. Light is traveling through water and suddenly breaks and surface and travels through air. Did light's speed increase, decrease, or stay the same once it left the water?
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Light's speed increased once it left the water.
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15.3 Without looking a Figure 15.2 or Figure 15.3, order the following colors in terms of increasing frequency: yellow, indigo, red, green
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red, yellow, green, indigo.
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15.4 If radio signals are really made up of light, why does't a radio station's antenna glow when it transmits its signals?
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The antenna doesn't glow because it's frequency is too low to see.
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6. Order the following colors in terms of increasing wavelength: orange, violet, yellow, green.
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violet, green, yellow, orange
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7. Order the colors (orange, violet, yellow, green) in terms of increasing frequency.
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orange, yellow, green, violet
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8. Do radio waves have higher or lower frequencies than visible light? What about X-rays?
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radio waves have lower frequencies than visible light. X-rays have higher frequencies than visible light.
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9. Infrared light is given off by any object that is losing heat. The human body is almost always losing heat to the environment. Why, then, don't human bodies glow at night, since they are emitting light?
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Human bodies don't glow at night because the light emitted from them is too low a frequency to be visible.
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1.a The Law of Reflection
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Then angle of reflection equals the angle of incidence.
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10. Light hits a mirror, making an angle of 15 degrees relative to a line drawn perpendicular to the mirror's surface. What angle does the reflected light make with the same line?
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a 15 degree angle
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11. In the following diagram, will the man see his foot, despite the fact that the mirror does not reach the ground?
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Yes, the man will see his foot.
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15.6 The following is a diagram of how a light ray travels from substance A through substance B: Does light travel faster in substance A or substance B?
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Light travels faster in substance B.
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15.7 A man is spear fishing. He looks into the water and sees a fish in front of him. When he aims his spear, should he aim it at the fish, in front of the fish, or behind the fish?
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in front of the fish
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12. When light travels from one substance to another, what two things can happen to the direction of the light ray's travel?
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It can be refracted and bend towards the perpendicular line or away form it. Or it can reflect at the same angle that the light ray hits the object.
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13. In a physics experiment, a light ray is examined as it travels from air into glass. If the angle that the light ray makes with a line perpendicular to the glass surface is measured, will the refracted ray bend toward or away from that line?
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the ray is bend towards the line.
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14. When you look at objects underwater from above the water, they appear to be at a different position than the position they are truly at. Why?
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Because when light travels from air to water it bends.
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15.8 Consider the two lenses pictured below. Which one focuses light rays closest to the lens?
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Lens (b) does
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13. In a physics experiment, a light ray is examined as it travels from air into glass. If the angle that the light ray makes with a line perpendicular to the glass surface is measured, will the refracted ray bend toward or away from that line.
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The refracted ray will bend towards the line.
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15. In order for you to see a rainbow, what three conditions must be met?
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1 the sun must be shining behind you 2 the sun must be at a certain angle 3 water droplets must be suspended in air
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16. What is the difference between a converging lens and a diverging lens?
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A converging lens brings light rays together in a focal point whereas a diverging lens sends them outwards.
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17. Which of the following lenses is a converging lens? Which is a diverging lens?
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(a) is a converging lens (b) is a diverging lens
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18. What is special about the way the eye focuses light as compared to the way a camera focuses light?
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the eye changes the shape of it's lens whereas the camera moves it's lens around.
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19. Suppose the come cells on your retina that sense red light no longer work. If you look at a white piece of paper, what color would it appear to be? If you looked at a red piece of paper, what color would it appear to be?
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The white piece of paper would look green/blue and the red piece of paper would look black.
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15.9 Suppose you have two flashlights. You cover the first with green cellophane and shine it on a mirror. When you look at the mirror, you see a green spot of light, If you were to then take the second flashlight, cover it with red cellophane, and shine it on the same part of the mirror that the green spot is still shining, what color would your see?
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Yellow
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15.10 Suppose you took a red shirt and put it in a dark room Then, suppose you took a flashlight and covered it with green cellophane as described above. If you were to go into the dark room and shine the green cellophane-covered flashlight on the red shirt, what color would you see?
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You'd see black
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20. A shirt is dyed so that it looks violet. What colors of light does the dye absorb?
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Red, Orange, Yellow, Green, Blue, and Indigo
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21. A cyan dye is made of a mixture of substances which absorb all light colors except blue and green. If you took a cyan piece of paper and placed it in a dark room and shined red light on it, what would you see? What would you see if you shined green light on it?
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The red light would show the paper black. The green light would show the paper green.
