Phys Int CC Ch 13 - Light - Answers PDF & Explantion PDF

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Answers Physics Intro. Lecture Notes. Full of answers. Find everything you need here. Answers from beginning of course to end of unit....

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CK-12 Physics Concepts - Intermediate Answer Key Chapter 13: Light 13.1 Fundamentals of Light Practice Questions 1. What wavelengths are included in the visible spectrum? 2. All colors of light mixed together produces _____________. 3. What is necessary for a rainbow to form? Answers 1. 400 nm to 700 nm 2. White light 3. Sunlight and water droplets Review Questions 1. Sound doesn’t travel through a vacuum because there are no molecules to carry it. How do we know that light does travel through a vacuum? 2. What is the range of wavelength of electromagnetic radiation the human eye can detect? 3. What was changed in the equation in this concept? 4. What color of visible light has the shortest wavelength? 5. How are we able to see objects that do not generate light? 6. Of what colors does white light consist? 7. Why can’t sound waves be polarized? 8. What happens to the wavelength of light as the frequency increases? 9. The sky appears darker when viewed through a polarizing filter. Why? 10. What color will a yellow banana appear when illuminated by a. white light? b. yellow light? c. blue light?

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Answers 1. We know light travels through a vacuum because electric and magnetic fields can still exist in a vacuum. Additionally, we know that space is a vacuum and that light from the sun reaches us on earth. 2. The human eye can detect approximately from 4 x 10-7 m to 8 x 10-7 m wavelengths. 3. v is changed to c because c is the velocity of electromagnetic waves. 4. Violet light has the shortest wavelengths. 5. We can see objects that do not generate light because we see the reflection of light off those objects. 6. White light consists of all the colors of the visible light spectrum. 7. Sound waves cannot be polarized because they consist of pulses of molecules, not electromagnetic fields. 8. As the frequency increases, the wavelength decreases. 9. The sky appears darker because not all the light waves can get through the polarizing filter. 10. a.) Yellow b.) Yellow c.) Black

13.2 Reflection of Light Practice Questions 1. Both the angle of incidence and the angle of reflection are measured from the ______. 2. In reflection, the angle of incidence __________ the angle of reflection. Answers 1. Normal of the material 2. Equals Review Questions 1. How does regular reflection differ from diffuse reflection? 2. If a light ray strikes a mirrored surface at an angle of 25° to the surface, what is the angle of incidence? 3. For problem #2, what will be the angle of reflection? 4. A dry cement road is a diffuse reflector. When it rains, the water fills in all the little holes and cracks in the cement road and it becomes a smooth regular reflector. At night, when you are depending on the light from your headlights to show you the

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lines on the road, a wet road becomes much darker and it is more difficult to see the lines. Explain why this occurs. Answers 1. In regular reflection, the light rays maintain their relative position, allowing the image to be maintained. In diffuse reflection off a rough surface, the reflected image is distorted, and even unidentifiable. 2. 3. 4. Since the light coming from the headlights of the car are reflected in many directions, the light will be reflected away from the lines on the road, thus failing to illuminate the lines on the road.

13.3 Refraction of Light Practice Questions 1. What happens to the path of a light beam when it enters a new medium at an angle? 2. Light moving from air into water is bent _____ the normal. 3. Light moving from water into air is bent _____ the normal. Answers 1. It bends at a different angle 2. Towards 3. Away from Review Questions 1. Light moving through air is incident on a piece of crown glass at an angle of 45O what is the angle of refraction? 2. A ray of light passes from air into water at an incident angle of 60O. Find the angle of refraction. 3. Light passes from water into a block of transparent plastic. The angle of incidence from the water is 31O and the angle of refraction in the block is 27O. What is the index of refraction for the plastic? 4. The index of refraction of water is 1.36. What is the speed of light in water? 5. If the speed of light in a piece of plastic is 2.00 X 108 m/s, what is the index of refraction for the plastic?

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Answers

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The angle of refraction is 27.72 degrees

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The angle of refraction is 39.55 degrees

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The index of refraction is 1.13

The speed of light in water is 2.2 X 108 m/s

The index of refraction for the plastic is 1.5

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13.4 Total Internal Reflection Practice Questions 1. What phenomenon occurs when light does not enter the new medium and remains in the old medium? 2. When does this phenomenon occur? Answers 1. Total Internal Reflection. 2. When the angle of incident is large (with water and air, larger than 48.8˚). Review Questions 1. Find the critical angle for light passing from diamond into air, given ndiamond = 2.42 2. When two swimmers are under water in a swimming pool, it is possible for the interface between the water and the air to act as a mirror allowing the swimmers to see images of each other. Explain this phenomenon. 3. Robert shines a laser beam through a slab of plastic and onto the interface between the slab of plastic and the air on the other side. The index of refraction for the plastic is 1.62. If the angle of incidence in the plastic is the plastic into the air? Answers

The critical angle is 24.41O

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2. If they are looking at a large enoug relatively calm surface, all the light will be internally reflected, allowing the swimmers to see each other.

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internal reflection. not pass out of the plastic.

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