# Behavior of Waves Review

Unit 3

1. A single disturbance that moves from point to point through a medium is called a ___.

 a. period b. periodic wave c. wavelength d. pulse

What is a Wave?

2. If the particles of the medium are vibrating to and fro in the same direction of energy transport, then the wave is a ____ wave.

 a. longitudinal b. sound c. standing d. transverse

Categories of Waves

3. When the particles of a medium are vibrating at right angles to the direction of energy transport, then the wave is a ____ wave.

 a. longitudinal b. sound c. standing d. transverse

Categories of Waves

4. A transverse wave is traveling through a medium. See diagram below. The particles of the medium are moving.

 a. parallel to the line joining AD. b. along the line joining CI. c. perpendicular to the line joining AD. d. at various angles to the line CI. e. along the curve CAEJGBI.

Categories of Waves

5. If the energy in a longitudinal wave travels from south to north, the particles of the medium would be moving ____.

 a. from north to south, only b. both north and south c. from east to west, only d. both east and west

Categories of Waves

6. As a pulse travels though a uniform medium, the speed of the pulse ____.

 a. decreases b. increases c. remains the same

The Speed of a Wave

7. The main factor which effects the speed of a sound wave is the ____.

 a. amplitude of the sound wave b. intensity of the sound c. loudness of the sound d. properties of the medium e. pitch of the sound

The Speed of a Wave

8. As a wave travels into a medium in which its speed increases, its wavelength would ____.

 a. decrease b. increase c. remain the same

The Wave Equation

9. As a wave passes across a boundary into a new medium, which characteristic of the wave would NOT change?

 a. speed b. frequency c. wavelength

The Speed of a Wave

10. What is the amplitude of the wave in the diagram below?

 a. 0.03 m. b. 0.04 m. c. 0.05 m. d. 0.06 m.

The Anatomy of a Wave

11. The wavelength of the wave in the diagram above (Question #10) is ____ m.

 a. 0.030 b. 0.040 c. 0.060 d. 0.080

The Anatomy of a Wave

12. A wave X meters long passes through a medium with a speed of Y meters per second. The frequency of the wave could be expressed as

 a. Y/X cycles/sec. b. X/Y cycles/sec. c. XY cycles/sec. d. (X + Y) cycles/sec.

The Wave Equation

Consider the following diagram for questions #13-14.

13. How many complete waves are shown in the diagram?

 a. 1 b. 2 c. 3 d. 1.5

14. If the distance from point A to point B in the diagram is 60 cm, then the wavelength is ____.

 a. 20 cm. b. 40 cm. c. 60 cm. d. 90 cm.

The Anatomy of a Wave

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.

Frequency and Period of a Wave

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 2.0 Hz and the wave speed is 5.0 m/s then the distance between adjacent wave crests is ___ meter.

 a. 0.20 b. 0.40 c. 1.25 d. 2.5 e. 10

The Anatomy of a Wave | The Wave Equation

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.

The Wave Equation

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

The Speed of a Wave

19. A pendulum makes 40 vibrations in 20 s. Its period is ____. (Be cautious of the units.)

 a. 0.50 Hz. b. 0.50 s. c. 2.0 Hz. d. 2.0 s. e. 8.0 x 102 Hz.

Frequency and Period of a Wave

20. A period of 0.0050 seconds would be equivalent to a frequency of ____ Hz.

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

Frequency and Period of a Wave

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

Frequency and Period of a Wave

22. TRUE or FALSE:

The SI unit for frequency is hertz.

 a. True b. False

Frequency and Period of a Wave

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

The Wave Equation

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.

The Wave Equation

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?

Boundary Behavior

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.

Boundary Behavior

27. Diagram P at the right shows a transverse pulse traveling along a dense rope toward its junction with a less dense rope. Which of the diagrams (A, B, C, D, or E) below depicts the ropes at the instant that the reflected pulse again passes through its original position marked X? Consider such features as amplitude and relative speed (i.e., the relative distance of the transmitted and reflected pulses from boundary).

Boundary Behavior

28. A wave whose speed in a snakey is 4.4 m/s enters a second snakey. The wavelength changes from 2.0 m to 3.0 m. The wave in the second snakey travels at ____.

 a. 1.46 m/s. b. 2.2 m/s. c. 2.9 m/s. d. 4.4 m/s. e. 6.6 m/s.

Boundary Behavior

29. The diagram at the right shows a disturbance moving through a rope towards the right. If this disturbance meets a similar disturbance moving to the left, then which one of the diagrams below depict a pattern which could NEVER appear in the rope?

Boundary Behavior

30. A 2.0-meter long rope is hanging vertically from the ceiling and attached to a vibrator. A single pulse is observed to travel to the end of the rope in 0.50 s. What frequency should be used by the vibrator to maintain three whole waves in the rope?

 a. 0.75 Hz b. 1.33 Hz c. 4.0 Hz d. 6.0 Hz e. 8.0 Hz

The Wave Equation

31. A Standing wave experiment is performed to determine the speed of waves in a rope. The standing wave pattern shown below is established in the rope. The rope makes 90 complete vibrational cycles in one minute. The speed of the waves is ____ m/s.

 a. 3 b. 6 c. 180 d. 360 e. 540

The Wave Equation

32. Consider the standing wave pattern shown below. A wave generated at the left end of the medium undergoes reflection at the fixed end on the right side of the medium. The number of antinodes in the diagram is

 a. 3. b. 5. c. 6. d. 7. e. 12.

Nodes and Anti-nodes

33. A node is a point located along the medium where there is always ___.

 a. a double crest. b. a double trough. c. constructive interference. d. destructive interference. e. a double rarefaction.

Nodes and Anti-nodes

34. TRUE or FALSE:

Constructive interference of waves occurs when two crests meet.

 a. True b. False

Interference of Waves

35. Which phenomenon is produced when two or more waves passing simultaneously through the same medium meet up with one another?

 a. refraction. b. diffraction. c. interference. d. reflection.

Interference of Waves

36. Two pulses are traveling in opposite directions along the same medium as shown in the diagram at the right. Which diagram below best depicts the appearance of the medium when each pulse meets in the middle?

Interference of Waves

37. TRUE or FALSE:

A vibrating object is necessary for the production of sound.
 a. True b. False

Sound is a Mechanical Wave

38. Which one of the following CANNOT transmit sound?

 a. Liquid air b. Gaseous oxygen c. Liquid water d. Solid steel e. Perfect vacuum

Sound is a Mechanical Wave