Mastering Physics- Refraction And Interference Lab 6tw3f

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Lab 14 (Refraction and Interference)

PHY110ASPRING2013

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Lab 14 (Refraction and Interference)

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Lab 14 (Refraction and Interference) Due: 11:59pm on Sunday, April 28, 2013 Note: To understand how points are awarded, read your instructor's Grading Policy.

Video: Refraction of Sound Watch the video, and then answer the following questions.

Part A What is the difference in the speed of sound on a warm day versus on a cold day?

Hint 1. Speed of sound waves. What happens to the speed of a sound wave when the temperature drops? ANSWER: It is equally fast on a cold or warm day. It is slower on a warm day and faster on a cold day. It is faster on a warm day and slower on a cold day.

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Correct

Part B Why did the campers in Dr. Hewitt’s story hear the sound of the campers across the lake more clearly at night than during the day?

Hint 1. Factors affecting speed of sound What factors affect the speed of sound in air? How do these factors change from day to night? ANSWER: Sound waves travel faster in the dark than in light. The ambient noises were gone, making it easier to hear the other campers. The temperature change from cold at the surface to warm at the top changed the shape of the sound waves.

Correct

Part C How does the direction of sound travel compare to the shapes of the sound waves?

Hint 1. Shape of the ripple and the direction of the wave When you throw a pebble into a still pool, in what direction does the wave advance? What is the shape of the ripple? ANSWER: The sound travels in the opposite direction from the arc of the crests of the waves. The sound is at right angles to the waves. The sound travels in the same direction as the arc of the crests of the waves.

Correct

Part D How does the cooler air above the lake affect the movement of sound at night?

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Hint 1. Speed of sound and temperature When sound es through cooler air, does it travel more slowly or faster? What does the change in speed do to a sound wave? ANSWER: The cooler temperature above the water refracts the sound wave away from the ground and toward the sky. Because it is colder just above the surface and warmer higher above, the sound wave is refracted toward the ground. Sound travels faster in cooler air.

Correct

Part E How do the waves of sound travel on the night that produces the temperature inversion, and why?

Hint 1. Temperature and speed of sound Do waves travel equally fast in warm and cold air? If not, in which type of air do they travel faster? How does this affect the direction in which they travel? ANSWER: The waves bend toward the ground because it is warmer above and colder lower below, and waves travel more slowly through the colder air. The waves travel in a straight line because waves always travel in a straight line. The waves bend toward the sky because it is warmer above and colder lower below, and waves travel faster through the colder air. The waves bend toward the sky because it is colder above and warmer lower below, and waves travel faster through the warmer air.

Correct

Interactive Figure: Constructive and Destructive Interference Explore the Interactive Figure to help you with the following set of questions. If you need more help, click on "How To Use" for more information. Change the amplitude and wavelength of each wave by adjusting the “Amplitude” and “Wavelength” sliders. Change the phase difference between the waves by adjusting the “Phase session.masteringphysics.com/myct/assignmentPrintView?assignmentID=2289672

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Lab 14 (Refraction and Interference)

change” slider. To change to the “Longitudinal Wave,” click the button at the bottom right. To change back to the “Transverse Wave,” click the button at the bottom right.

Part A Given a wave of a particular wavelength and amplitude, what must be the amplitude, wavelength, and phase change of a wave you add to this wave to create a wave of twice the amplitude?

Hint 1. Alignment and size of crests and troughs for doubling a wave To create a wave of twice the amplitude, how must the crests and troughs in the wave that you add align with the crests and troughs in the given wave? What should the size of the crests and troughs of these waves be? And how often should they occur? ANSWER: The added wave must have the same amplitude, the same wavelength, and a phase difference of 180 degrees with respect to the original wave. The added wave must have twice the amplitude, twice the wavelength, and a phase difference of 0 degrees with respect to the original wave. The added wave must have the same amplitude, the same wavelength, and a phase difference of 0 degrees with respect to the original wave. The added wave must have twice the amplitude, the same wavelength, and a phase difference of 180 degrees with respect to the original wave. The added wave must have the same amplitude, twice the wavelength, and a phase difference of 0 degrees with respect to the original wave.

Correct

Part B Given a wave of a particular wavelength and amplitude, what must be the amplitude, wavelength, and phase change of a wave you add to the existing wave to completely destroy it? session.masteringphysics.com/myct/assignmentPrintView?assignmentID=2289672

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Hint 1. Alignment and size of crests and troughs for destroying a wave To completely destroy a wave, how must the crests and troughs in the wave that you add to it align with the crests and troughs in the given wave? What should the size of the crests and troughs of these waves be? And how often should they occur? ANSWER: The added wave must have twice the amplitude, twice the wavelength, and a phase difference of 0 degrees with respect to the original wave. The added wave must have the same amplitude, the same wavelength, and a phase difference of 0 degrees with respect to the original wave. The added wave must have twice the amplitude, the same wavelength, and a phase difference of 180 degrees with respect to the original wave. The added wave must have the same amplitude, the same wavelength, and a phase difference of 180 degrees with respect to the original wave. The added wave must have the same amplitude, twice the wavelength, and a phase difference of 0 degrees with respect to the original wave.

Correct

Part C For maximum constructive interference between two waves, how must their crests and troughs align with each other?

Hint 1. Alignment of crests and troughs for maximum constructive interference Maximum constructive interference means that the crests and troughs superimpose each other. How should the crests and troughs of one wave align with the crests and troughs of the other wave for that to happen? ANSWER: The crests and troughs of one wave should align with the troughs and crests of the other wave respectively. The crests and troughs of one wave should align with the zero crossing points of the other wave. The crests and troughs of one wave should align with the crests and troughs of the other wave respectively.

Correct

Part D session.masteringphysics.com/myct/assignmentPrintView?assignmentID=2289672

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For complete destructive interference between two waves, how must their crests and troughs align with each other?

Hint 1. Alignment of crests and troughs for destruction Complete destructive interference means that the crests and troughs destroy each other. How should the crests and troughs of one wave align with the crests and troughs of the other wave for that to happen? ANSWER: The crests and troughs of one wave should align with the troughs and crests of the other wave respectively. The crests and troughs of one wave should align with the zero crossing points of the other wave. The crests and troughs of one wave should align with the crests and troughs of the other wave respectively.

Correct Score Summary: Your score on this assignment is 82.5%. You received 1.65 out of a possible total of 2 points.

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