# Basics of Waves Review

 Navigate to Answers for: [ Questions #1-#14 | Questions #15-#26 | Questions #27-#38 ] [ #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | #11 | #12 | #13 | #14 ]

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

 Answer: D A wave is a continuous and repeating disturbance of a medium and a pulse is a single disturbance.

What is a Wave?

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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

 Answer: A In longitudinal waves, particles of the medium vibrate to and from in a direction parallel to the direction of energy transport. If energy is transmitted along a medium from the east end to the west end, then particles of the medium would vibrate eastward and westward A sound wave is a longitudinal wave but not the answer since a wave which exhibits this characteristic is not necessarily a sound wave.

Categories of Waves

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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

 Answer: D In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.

Categories of Waves

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

 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.
 Answer: A In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport. In this case, that would be parallel to the line AD.

Categories of Waves

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

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

 Answer: B In longitudinal waves, particles of the medium vibrate to and from in a direction parallel to the direction of energy transport. If the particles only moved north and not back south, then the particles would be permanently displaced from their rest position; this is not wavelike.

Categories of Wave

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

 a. decreases b. increases c. remains the same

 Answer: C The speed of a wave or a pulse depends upon the properties of the medium. If the medium is uniform or unchanging, then the speed is constant.

The Speed of a Wave

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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

 Answer: D The speed of a wave is dependent upon the properties of the medium and not the properties of the wave.

The Speed of a Wave

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

 a. decrease b. increase c. remain the same

 Answer: B As a wave crosses a boundary into a new medium, its speed and wavelength change while its frequency remains the same. If the speed increases, then the wavelength must increase as well in order to maintain the same frequency.

The Wave Equation

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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

 Answer: B As a wave crosses a boundary into a new medium, its speed and wavelength change while its frequency remains the same.

The Speed of a Wave

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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.

 Answer: A The amplitude of a wave is measured from rest to crest or from rest to trough; but not from crest to trough. Thus, take the 0.06 m measurement and "halve it" to get the answer.

The Anatomy of a Wave

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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

 Answer: D The wavelength of a wave is measured as the distance between any two corresponding points on adjacent waves, which would mean from a crest to the next adjacent crest. Thus, the distance from point b to point d is the wavelength - 0.08 m

The Anatomy of a Wave

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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.

 Answer: A Let d = wavelength. Since d*f = v, f = v/d.

The Wave Equation

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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

 Answer: D From point A to point E is one full wave cycle. After point E, the wave begins to repeat itself, but only for one-half of a cycle. Thus, there are 1.5 waves shown in the diagram.

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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.

 Answer: B From point A to point E is one full wave cycle. This distance represents two-thirds of the 60 cm from A to G. Thus, the wavelength is (2/3)*60 cm = 40 cm.