# Chapter 12 Pretest Waves.

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Chapter 12 Pretest Waves

1. Vibrating particles that are in phase have the: A) same displacement and same direction of motion, B) same displacement and opposite direction of motion, C) opposite displacement and same direction of motion, D) opposite displacement and opposite direction of motion, E) who cares?

1. Vibrating particles that are in phase have the: A) same displacement and same direction of motion, B) same displacement and opposite direction of motion, C) opposite displacement and same direction of motion, D) opposite displacement and opposite direction of motion, E) who cares?

2. Which statement about a ripple tank is not true
2. Which statement about a ripple tank is not true? A) Surface waves are easy to produce B) Surface waves move slowly. C) An image of surface waves can be projected on a screen. D) In the projected image a wave crest appears dark.

2. Which statement about a ripple tank is not true
2. Which statement about a ripple tank is not true? A) Surface waves are easy to produce B) Surface waves move slowly. C) An image of surface waves can be projected on a screen. D) In the projected image a wave crest appears dark.

3. In an interference pattern, the points of maximum displacement are: A) nodes, B) loops, C) crests, D) troughs.

3. In an interference pattern, the points of maximum displacement are: A) nodes, B) loops, C) crests, D) troughs.

4. Which of these expressions is not equal to the others
4. Which of these expressions is not equal to the others? A) 50 cycles, B) 50/s, C) 50 s-1, D) 50 Hz.

4. Which of these expressions is not equal to the others
4. Which of these expressions is not equal to the others? A) 50 cycles, B) 50/s, C) 50 s-1, D) 50 Hz.

5. The period of a wave and its frequency are: A) unrelated, B) equal, C) reciprocals, D) directly proportional.

5. The period of a wave and its frequency are: A) unrelated, B) equal, C) reciprocals, D) directly proportional.

6. Which of the following is NOT useful in generating and transmitting mechanical waves? A) an elastic medium, B) a vacuum, C) a source of energy, D) a material that behaves as if it were made of particles connected by springs, with each particle having an equilibrium position.

6. Which of the following is NOT useful in generating and transmitting mechanical waves? A) an elastic medium, B) a vacuum, C) a source of energy, D) a material that behaves as if it were made of particles connected by springs, with each particle having an equilibrium position.

7. Here are five possible requirements for superposition to occur:. 1
7. Here are five possible requirements for superposition to occur: 1. Two or more waves are needed. 2. The waves travel through different media. 3. The waves travel through the same medium. 4. The waves travel simultaneously. 5. The waves travel at different times. The correct combination of requirements is: A) 1,2, and 4, B) 1,2, and 5, C) 1, 3, and 4, D) 1, 3, and 5.

7. Here are five possible requirements for superposition to occur:. 1
7. Here are five possible requirements for superposition to occur: 1. Two or more waves are needed. 2. The waves travel through different media. 3. The waves travel through the same medium. 4. The waves travel simultaneously. 5. The waves travel at different times. The correct combination of requirements is: A) 1,2, and 4, B) 1,2, and 5, C) 1, 3, and 4, D) 1, 3, and 5.

8. A mass attached to a spring vibrates back and forth
8. A mass attached to a spring vibrates back and forth. At maximum displacement, the spring force and the: a. velocity reach a maximum b. velocity reach zero. c. acceleration reach a maximum d. acceleration reach zero.

8. A mass attached to a spring vibrates back and forth
8. A mass attached to a spring vibrates back and forth. At maximum displacement, the spring force and the: a. velocity reach a maximum b. velocity reach zero. c. acceleration reach a maximum d. acceleration reach zero.

9. Which of the following is the time it takes to complete a cycle of motion? a. amplitude b. period c. frequency d. acceleration

9. Which of the following is the time it takes to complete a cycle of motion? a. amplitude b. period c. frequency d. acceleration

10. A musical tone sounded on a piano has a frequency of 410 Hz and a wavelength of 0.80 m. What is the speed of the sound wave? A. 170 m/s B. 240 m/s C. 330 m/s D. 590 m/s

10. A musical tone sounded on a piano has a frequency of 410 Hz and a wavelength of 0.80 m. What is the speed of the sound wave? A. 170 m/s B. 240 m/s C. 330 m/s D. 590 m/s

11. A student sends a pulse traveling on a taut rope with one end attached to a post. What will the student observe? A. The pulse will not be reflected if the rope is free to slide up and down on the post. B. The pulse will be reflected and inverted if the rope is free to slide up and down on the post. C. The pulse will be reflected and inverted if the rope is fixed to the post. D. The pulse will not be inverted if the rope is fixed to the post.

11. A student sends a pulse traveling on a taut rope with one end attached to a post. What will the student observe? A. The pulse will not be reflected if the rope is free to slide up and down on the post. B. The pulse will be reflected and inverted if the rope is free to slide up and down on the post. C. The pulse will be reflected and inverted if the rope is fixed to the post. D. The pulse will not be inverted if the rope is fixed to the post.

1. Draw a sketch of a device that can generate periodic transverse waves. On your sketch, label crest, trough, wavelength, and amplitude; identify two particles that are in phase and two particles that are in opposite phase.

The high points are the crests; the low points are the troughs
The high points are the crests; the low points are the troughs. Two crests are in the same phase; a crest and a trough are in opposite phase.

2. A sound having a frequency of 264 Hz travels through air at 341 m/s
2. A sound having a frequency of 264 Hz travels through air at 341 m/s. What is the wavelength of the sound?

v = f l 341 = 264 x l l = 1.29 m

3. Green light, wavelength 5
3. Green light, wavelength 5.20 X 10-7 m, travels through air at a speed of 3.00 X 108 m/s. Calculate the frequency and period of green light waves.

v = f l 3.00 X 108 = f x 5.20 X 10-7 f = 5.77 x 1014 Hz 1/5.77 x 1014 = 1.74 x 10-15 s

4. How is the relationship between period and frequency represented as an equation?

T = 1/f or f = 1/T