## Basics of Waves Review

#### Navigate to:

Review Session Home - Topic Listing

Waves - Home || Printable Version || Questions with Links

Answers to Questions:  All || #1-#14 || #15-#26 || #27-#38

 [ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

15. The number of cycles of a periodic wave occurring per unit time is defined as a wave's ____.

 a. wavelength. b. period. c. amplitude. d. frequency.

 Answer: D This is a basic definition which you should know and be able to apply.

 Useful Web Links Frequency and Period of a Wave

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

16. A periodic and repeating disturbance in a lake creates waves which emanate outward from its source to produce circular wave patterns. If the frequency of the source is 2.00 Hz and the wave speed is 5.00m/s then the distance between adjacent wave crests is ___ meter.

 a. 0.200 b. 0.400 c. 1.25 d. 2.50 e. 10.0

 Answer: D Let w=wavelength; then v = w*f. In this problem, it is given that v=5.00 m/s and f = 2.00 Hz. Substitution and algebra yields w = v / f = 2.50 m.

 Useful Web Links The Anatomy of a Wave | The Wave Equation

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

17. What is the frequency of a wave that has a speed of 0.4 m/s and a wavelength of 0.020 meter?

 a. 10 hertz. b. 20 hertz. c. 0.008 hertz. d. 0.5 hertz.

 Answer: B Let w=wavelength; then v = w*f. In this problem, it is given that v=5 m/s and w = .02 m. Substitution and algebra yields f=v/w=20 Hz.

 Useful Web Links The Wave Equation

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

18. Many wave properties are dependent upon other wave properties. Yet, one wave property is independent of all other wave properties. Which one of the following properties of a wave is independent of all the others?

 a. wavelength b. frequency c. period d. velocity

 Answer: D The speed of a wave is dependent upon the properties of the medium through which it moves, not upon the properties of the wave itself.

 Useful Web Links The Speed of a Wave

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

19. A pendulum makes exactly 40 vibrations in 20.0 s. Its period is ____. (Be cautious of the units.)

 a. 0.500 Hz. b. 0.500 s. c. 2.00 Hz. d. 2.00 s. e. 8.00 x 102 Hz.

 Answer: B The period is the time for one complete cycle. If the pendulum takes 20.0 seconds for exactly 40 vibrational cycles, then it must take 0.500 second for one cycle.

 Useful Web Links Frequency and Period of a Wave

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

20. A period of 0.005 seconds would be equivalent to a frequency of ____ Hz.

 a. 20 b. 50 c. 200 d. 500 e. 2000

 Answer: C The period and the frequency are related by a reciprocal relationship; that is, f = 1/T.

 Useful Web Links Frequency and Period of a Wave

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

21. TRUE or FALSE:

The number of waves generated per second by a source is called the frequency of the source.
 a. True b. False

 Answer: A This is a basic definition which you should know and be able to apply.

 Useful Web Links Frequency and Period of a Wave

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

22. TRUE or FALSE:

The SI unit for frequency is hertz.
 a. True b. False

 Useful Web Links Frequency and Period of a Wave

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

23. TRUE or FALSE:

Doubling the frequency of a wave source (without altering the medium) doubles the speed of the waves.
 a. True b. False

 Answer: B Don't be fooled. Wave speed may equal frequency*wavelength. Yet doubling the frequency only halves the wavelength; wave speed remains the same. To change the wave speed, the medium would have to be changed.

 Useful Web Links The Wave Equation

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

24. If the frequency of a wave is doubled and if the speed remains constant, its wavelength is ____.

 a. quartered. b. halved. c. unchanged. d. doubled.

 Answer: B Wave speed equals frequency*wavelength. So doubling the frequency must halve the wavelength in order for wave speed to remain the same.

 Useful Web Links The Wave Equation

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

25. Two different ropes with different mass densities are attached to each other. A pulse is introduced into one end of the rop and approaches the boundary as shown at the right. At the boundary, a portion of the energy is transmitted into the new medium and a portion is reflected. Which one of the diagrams below depicts the possible location and orientation of the pulse shortly after the incident pulse reaches the boundary?

 Answer: C The speeds in the two media can be deduced by the distance of the pulses from the boundary. In A and E, the speed is shown as fastest on the right, which makes the transmitted medium the less dense. Rule out A and E since a reflected pulse should not invert when moving from more dense to less dens. Rule out B for just the opposite reasons; the wave is moving from less to more dense and should invert upon reflection. Rule out D because the transmitted pulse never inverts. That leaves C as the answer.

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

26. When a pulse reaches a boundary between two different media, it will be____.

 a. reflected, only. b. transmitted, only. c. partly reflected and partly transmitted. d. neither reflected nor transmitted.

 Answer: C This is basic information about the boundary behavior of waves.

[ #15 | #16 | #17 | #18 | #19 | #20 | #21 | #22 | #23 | #24 | #25  | #26 ]

#### Navigate to:

Review Session Home - Topic Listing

Waves - Home || Printable Version || Questions with Links

Answers to Questions:  All || #1-#14 || #15-#26 || #27-#38

## You Might Also Like ...

Users of The Review Session are often looking for learning resources that provide them with practice and review opportunities that include built-in feedback and instruction. If that is what you're looking for, then you might also like the following:

The Calculator Pad includes physics word problems organized by topic. Each problem is accompanied by a pop-up answer and an audio file that explains the details of how to approach and solve the problem. It's a perfect resource for those wishing to improve their problem-solving skills.

Visit: The Calculator Pad Home | Calculator Pad - Vibrations and Waves

2. Minds On Physics the App Series

Minds On Physics the App ("MOP the App") is a series of interactive questioning modules for the student that is serious about improving their conceptual understanding of physics. Each module of the series covers a different topic and is further broken down into sub-topics. A "MOP experience" will provide a learner with challenging questions, feedback, and question-specific help in the context of a game-like environment. It is available for phones, tablets, Chromebooks, and Macintosh computers. It's a perfect resource for those wishing to refine their conceptual reasoning abilities. Part 5 of the series includes topics on Wave Motion.

Visit: MOP the App Home || MOP the App - Part 5