(13%) Problem 8: An audio engineer takes decibel readings at distances of r1 =15 m and r2 = 24 m from a concert stage speaker during a sound check. When he is r1 from the speaker, the engineer registers a decibel level of AB1 = 118 dB on his loudness meter. Randomized Variables "1 = 15 m 2 = 24 m 31 = 118 dB Elder, Lauren - Laurenmarieelder@gmail.com @theexpertta.com - tracking id: 5N67-9D-3B-44-99C3-13365. In accordance with Expert TA's Terms of Service. copying this information to any solutions sharing website is strictly forbidden. Doing so may result in termination of your Expert TA Account. 33% Part (a) What is the intensity of the sound, I1, in watts per square meter, that is measured by the loudness meter when the engineer is a distance of r From the speaker? I1 = 0.63 v Correct! 33% Part (b) How much power P, in watts, is coming from the speaker during the sound check at distance ri? P = 1800 V Correct! 33% Part (c) Assuming that the speaker output does not change between the two measurements at ri and r2, what sound intensity level B2, in decibels, will the loudness meter report when the engineer is at a distance r2 from the speaker? Grade Summary B2 = Deductions 8% Potential 92%

(13%) Problem 8: An audio engineer takes decibel readings at distances of r1 =15 m and r2 = 24 m from a concert stage speaker during a sound check. When he is r1 from the speaker, the engineer registers a decibel level of AB1 = 118 dB on his loudness meter. Randomized Variables "1 = 15 m 2 = 24 m 31 = 118 dB Elder, Lauren - Laurenmarieelder@gmail.com @theexpertta.com - tracking id: 5N67-9D-3B-44-99C3-13365. In accordance with Expert TA's Terms of Service. copying this information to any solutions sharing website is strictly forbidden. Doing so may result in termination of your Expert TA Account. 33% Part (a) What is the intensity of the sound, I1, in watts per square meter, that is measured by the loudness meter when the engineer is a distance of r From the speaker? I1 = 0.63 v Correct! 33% Part (b) How much power P, in watts, is coming from the speaker during the sound check at distance ri? P = 1800 V Correct! 33% Part (c) Assuming that the speaker output does not change between the two measurements at ri and r2, what sound intensity level B2, in decibels, will the loudness meter report when the engineer is at a distance r2 from the speaker? Grade Summary B2 = Deductions 8% Potential 92%

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter17: Physics Of Hearing

Section: Chapter Questions

Problem 61PE: Based on the graph in Figure 17.36, what is the threshold of hearing in decibels for frequencies of...

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The area of a typical eardrum is about 5.00 X 10-5 m2. (a) (Calculate the average sound power incident on an eardrum at the threshold of pain, which corresponds to an intensity of 1.00 W/m2. (b) How much energy is transferred to the eardrum exposed to this sound lor 1.00 mill?
A sound wave in air has a pressure amplitude equal to 4.00 103 Pa. Calculate the displacement amplitude of the wave at a frequency of 10.0 kHz.
Some studies suggest that the upper frequency limit of hearing is determined by the diameter of the eardrum. The wavelength of the sound wave and the diameter of the eardrum are approximately equal at this upper limit. If the relationship holds exactly, what is the diameter of the eardrum of a person capable of hearing 20 000 Hz? (Assume a body temperature of 37.0C.)
Based on the graph in Figure 17.36, what is the threshold of hearing in decibels for frequencies of 60, 400, 1000, 4000, and 15,000 Hz? Note that many AC electrical appliances produce 60 Hz, music is commonly 400 Hz, a reference frequency is 1000 Hz, your maximum sensitivity is near 4000 Hz, and many older TVs produce a 15,750 Hz whine. Figure 17.36 The relationship of loudness in phons to intensity level (in decibels) and intensity (in watts per meter squared) for persons with normal hearing. The curved lines are equal-loudness curves—all sounds on a given curve are perceived as equally loud. Phons and decibels are defined to be the same at 1000 Hz.
A siren mounted 011 the roof of a firehouse emits sound at a frequency of 900 Hz. A steady wind is blowing with a speed of 15.0 m/s. Taking the speed of sound in calm air to be 343 m/s. find the wavelength of the sound (a) upwind of the siren and (b) downwind of the siren. Firefighters are approaching the siren from various directions at 15.0 m/s. What frequency does a firefighter hear (c) if she is approaching from an upwind position so that site is moving in the direction in which the wind is blowing and (d) if she is approaching from a downwind position and moving against the wind?
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As you travel down the highway in your car, an ambulance approaches you from the rear at a high speed (Fig. OQ13.15) sounding its siren at a frequency of 500 Hz. Which statement is correct? (a) You hear a frequency less than 500 Hz. (b) You hear a frequency equal to 500 Hz. (c) You hear a frequency greater than 500 Hz. (d) You hear a frequency greater than 500 Hz, whereas the ambulance driver hears a frequency lower than 500 Hz. (e) You hear a frequency less than 500 Hz, whereas the ambulance driver hears a frequency of 500 Hz. Figure OQ13.15
As you travel down the highway in your car, an ambulance approaches you from the rear at a high speed (Fig. OQ17.3) sounding its siren at a frequency of 500 Hz. Which statement is correct? (a) You hear a frequency less than 500 Hz. (b) You hear a frequency equal to 500 Hz. (c) You hear a frequency greater than 500 Hz. (d) You hear a frequency greater than 500 Hz. whereas the ambulance driver hears a frequency lower than 500 Hz. (e) You hear a frequency less than 500 Hz. whereas (he ambulance driver hears a frequency of 500 Hz.
A tuning fork is known to vibrate with frequency 262 Hz. When it is sounded along with a mandolin siring, four beats are heard every second. Next, a bit of tape is put onto each line of the tuning fork, and the tuning fork now produces five beats per second with the same mandolin siring. What is the frequency of the string? (a) 257 Hz (b) 258 Hz (c) 262 Hz (d) 266 Hz (e) 267 Hz
A barrel organ is shown in Figure P18.38. Such organs are much smaller than traditional organs, allowing them to fit in smaller spaces and even allowing them to be portable. Use the photo to estimate the range in fundamental frequencies produced by the organ pipes in such an instrument. Assume the pipes are open at both ends. How does that range compare to a piano whose strings range in fundamental frequency from 21.7 Hz to 4186.0 Hz? FIGURE P18.38