Honors Physics Burns. Multiple Choice: Identify the choice that best completes the statement or answers the question. / ~.

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1 Name: ~ Test Chapter 12 (Sound) Period Date: Honors Physics Burns /2010 Multiple Choice: Identify the choice that best completes the statement or answers the question. / ~./~ t~ ~ ~ 1. Sound waves a. are a part of the electromagnetic spectrum. b, do not require a medium for transmission. ~ are longitudinal waves. are transverse waves. 2. The trough of the sine curve used to represent a sound wave con esponds to a a compression, c. the amplitude. b. the wavelength. ~ a rarefaction. 3. Which of the following is the region of a sound wave in which the density and pressure are greater than normal? a. rarefaction c. amplitude Q~ compression d. wavelength 4. The highness or lowness of a sound is perceived as a. compression, c ultrasound. b. wavelength. (~ pitch. Pitch depends on the of a sound wave. frequency c. power amplitude d speed 6. Of the following nlaterials, sound waves travel fastest through,~. helium at 0 C. ~. copper at 0 C. 0. airat0 C, d. air at l00 C. 7. In general, sound travels faster through lids than through gases, c. gases than through liquids.~goa ses than through solids d. empty space than through matter. ~. )//At a large distance from a sound source, spherical wave fronts are viewed as ~ "~ ~" U a.~wavelengths. ~/L~/. rays. plane waves A train moves down the track t~wa~2d~an observer. The sound from the train, as heard by the observer, is the sound heard by a passenger on the train. a. the same as ~)%igher in pitch than b. a different timbre than d. lower in pitch thma 10. ~1~ If you are on a train, how will the pitch of the train s whistle sound to you as the train moves? a. The pitch will become steadily higher. b. The pitch will become steadily lower. O The pitch will not change. d. The pitch will become higher, then become lower. 11. If the intensity of a sound is!ncreased by a factor of 100, the new decibel level will increase a. by two units.,c. by a factor of 10. (~ t? twice the old one. d. by 20 units..2. A sound twice the intensity of 60 d~s ~ba~g~a how inany decibels? 63dB d. 120dB

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3 13. When the frequency of a force applied to a system matches the natural frequency of vibration of the system, occurs. a. damped vibration c. timbre b. random vibration (/~ resonance,4. For a standing wave in an air column in a pii~that is open at both ends, there must be a~t least a. one node and one antinode. ~,~ two antinodes and one node. ~... two nodes and one antinode. ~. two nodes and two antinodes If a guitar string has a fundamental frequency of 500 Hz, what is the frequency of its second harmonic? a. 250 Hz Qc.,~) 1000 b. 750Hz d. 2000Hz t6. The quality of a musical tone of a certain pitch results from a combination of a. fundamental frequencies, c. transverse waves. ~ 1~. harmo~i~s.~ d. velocities. 17. Musical instruments of different types playing the same note may often be identified by the of their sounds. a. pitch c. fundamental frequency b, intensity ~ ~y~ -F~ 18. How many beats per second are heard when two vibrating tuning forks having frequencies of 216 Hz and 224 Hz are held side by side? a, 6 Hz c. 9 Hz ~i~ff~ :z~ d. 3 Hz 19. A vibrating guitar string emits a tone just as a 5.00 x l(0~clz tuning fork is struck. If five beats per second are heard, which of the following is a possible frequency of vibration of the string? ~, 2500Hz c. 605Hz ~. 1500Hz ~ d. 495 Hz (a) (b) 20. In the figure shown above, a beat occurs at a. t.g c. d. t!and ~

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5 Problem Solving: SHOW ALL WORK! An engineer at an underwater military station listens for submarines by sending an ultrasound sonar ping that has a frequency of 3.75 MHz. [~ PO a. A stationary object is detected when the ping returns 3.00 s later. How far away is this object? The speed of sound in seawater is 1533 m!s. --d b. A second ping returns with a frequency of 3.80 MHz, indicating that the object is now moving.station? Whatf/is the= object s,~ ~~vel city?v -~. V ~In/which direction/is it moving relative to the listening@ Sonar equipment has difficulty detecting objects smaller than the wavelength of the ping. Old sonar equipment used an audible ping with a frequency of 400 Hz. What is the smallest,~ ~ object this old sonar could distinguish?

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7 A train whistle has a fundamental frequency of 880 Hz and a wavelength of m. What is the speed of this sound in air? b. What temperature is the air? c. If the whistle is a closed pipe, then how long is it? o,3~ -) If the next harmonic were to be heard in the closed pipe, how long would the pipe have 1 ~... / / 3. A 00-Hz tone must have what sound level to seem as loud as a~0-hz tone that has a 50-dB sound level? Briefly explain why this is so, referring to the graph in your explanation,

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9 4. A physics teacher sets up a 0.92 m long open tube to resonate at its fundamental frequency. Draw a diagram of the standing wave in the tube. b. What is the wavelength of the wave if room temperature is 27.3? c. What is the fundamental frequency of the sound? What is the fifth overtone in the open tube? 5. A boy drops a stone offofa cliff. If it takes 2.4 s until the sound of the splash is heard, high is the cliff?. ~ "~ ~ 3 ~/3 ~ ~-,~,~o ~ 2 ~ ~"~ g~

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