Topic : Sound

Questions 1 to 25: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer.

1. If a wave hits a smooth surface at an angle of incidence of 40 degrees, the angle of reflection is

A. 90 degrees.
B. 0 degrees.
C. 40 degrees.
D. 80 degrees.

2. Sound waves can't travel through

A. a liquid.
B. a solid.
C. an elastic material.
D. a vacuum.

3. If two waves with equal amplitudes and wavelengths travel through a medium in such a way that a particular particle of the medium is at the crest of one wave and at the trough of the other wave at the same time, what will happen to that particle?

A. The particle will cause beats as a result of the wave combination.
B. The particle will remain stationary due to interference.
C. The particle will vibrate with double amplitude due to resonance.
D. The particle will move halfway to the crest due to reinforcement.

4. Which one of the following frequencies of a wave in the air can be heard as an audible sound by the human ear?

A. 1,000 Hz
B. 100,000 Hz
C. 10 Hz
D. 0.10 Hz

5. In a stringed musical instrument, the sound frequency of a particular string can be increased by

A. lengthening the string.
B. tightening the string.
C. loosening the string.
D. increasing the string's thickness.

6. If you were trying to build a soundproof room, which of the following materials would you choose in order to absorb the most sound, based on the coefficient of absorption for each material?

A. Heavy curtains
B. Concrete
C. Carpet
D. Wood

7. During the process of steel production, the flaws in steel casting are detected by

A. resonant vibrations.
B. infrasonic vibrations.
C. ultrasonic vibrations.
D. longitudinal vibrations.

8. The change in pitch of a train's horn as it passes while you are standing still can be explained by

A. resonance.
B. the Doppler effect.
C. sympathetic vibration.
D. ultrasonic vibrations.

9. Which of the following phenomena is taking place when sound waves are reflected from a surface along parallel lines?

A. Focusing
B. Refracting
C. Diffusion
D. Absorption

10. The wavelength of a wave is the distance between

A. the crest and the following trough.
B. the amplitude and the normal position.
C. the rarefaction and the following compression.
D. two consecutive crests.

11. The function of the eardrum in the middle ear is to

A. vibrate with the frequency of the received sound.
B. carry the sound energy to the brain.
C. collect the sound waves.
D. amplify the received sound.

12. The number of waves that pass a particular point in a body in a unit of time is called the _______ of the waves.

A. rarefaction
B. frequency
C. compression
D. amplitude

13. Which one of the following environments will sound not travel through?

A. Gas
B. Liquid
C. Vacuum
D. Solid

14. The distance from one molecule in a body to the nearest molecule in the body occupying a similar position and moving in the same direction is a

A. rarefaction.
B. compression.
C. refraction.
D. wavelength.

15. The multiple reflection of a single sound wave is a/an

A. reverberation.
B. refraction.
C. echo.
D. diffraction.

16. The spreading of sound waves around openings in barriers is called

A. refraction.
B. an echo.
C. diffraction.
D. reverberation.

17. The _______ of a sound wave is defined as the amount of energy passing through a unit area of the wave front in a unit of time.

A. compression
B. intensity
C. frequency
D. amplitude

18. Through which one of the following mediums is the velocity of a sound wave the greatest?

A. Steel
B. Water
C. Lead
D. Air

19. In a stringed musical instrument, the part that vibrates in resonance with the sound waves produced by the strings is called the

A. sounding board.
B. reed.
C. membrane.
D. diatonic scale.

20. In a transverse wave that travels through a medium, the molecules of the medium vibrate

A. with smaller amplitudes than the molecules in a longitudinal wave.
B. in the direction in which the wave travels.
C. at right angles to the direction in which the wave travels.
D. at twice the velocity of the molecules in a longitudinal wave.

21. Rarefaction occurs only in a _______ wave.

A. sympathetic.
B. forced.
C. transverse.
D. longitudinal.

22. When the temperature of the air is 25°C, the velocity of a sound wave traveling through the air is approximately

A. 347 m/s.
B. 320 m/s.
C. 332 m/s.
D. 357 m/s.

23. A surface receiving sound is moved from its original position to a position three times farther away from the source of the sound. The intensity of the received sound thus becomes

A. nine times as high.
B. three times as high.
C. three times as low.
D. nine times as low.

24. The maximum distance a molecule has been moved from its normal position by a wave is

A. rarefaction.
B. compression.
C. frequency.
D. amplitude.

25. When a sound from a source is refracted away from the surface of the earth, it gives an indication that the

A. wind is blowing in the direction of the sound.
B. air is cooler than the ground.
C. ground is cooling faster than the air.
D. air has high humidity.