Concept explainers
Ever since seeing Figure 16.22 in the previous chapter, you have been fascinated with the hearing response in humans. You have set up an apparatus that allows you to determine your own threshold of hearing as a function of frequency. After performing the experiment and recording the results, you graph the results, which look like Figure P17.22. You are intrigued by the two dips in the curve at the right-hand side of the graph. You measure carefully and find that the minimum values of these dips occur at 3 800 Hz and 11 500 Hz. Performing some online research, you discover that the outer canal of the human ear can be modeled as an air column open at the outer end and closed at the inner end by the eardrum. You use this information to determine the length of the outer canal in your car.
Figure P17.22
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Chapter 17 Solutions
Physics for Scientists and Engineers with Modern Physics
- 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.)arrow_forwardSound is detected when a sound wave causes the eardrum to vibrate (as shown). Typically, the diameter of the eardrum is about 8.4 mm in humans. When someone speaks to you in a normal tone of voice, the sound intensity at your ear is approximately 1.0 × 10-6 W/m2. How much energy is delivered to your eardrum each second?arrow_forwardHow do we identify a high-pitched sound?A. High frequencies cause only weak vibrations of the basilar membrane.B. Each frequency produces a peak response at one point along the basilar membrane.C. The whole basilar membrane vibrates in synchrony with the sound frequency.D. Each frequency vibrates a different part of the pinna.arrow_forward
- q32 You work at a building site and the noise level has been measured at 95 dB. You need to wear earplugs rated to reduce the sound intensity by 32 dB. If your eardrum has a diameter of 8.4 mm, what is the power received by one eardrum before you put in an earplug. Question 32 options: A) 1.75 x 10^-7 W B) 4.42 x 10^-10 W C) 1.11 x 10^-4 W D) 1.11 x 10^-10 Warrow_forwardWhat is the speed of sound, in the unit of m/s, in a medium that has density of ρ = 792 kg/m3 and bulk modulus of B = 823 MPa?arrow_forwardWhat should be the power output of a speaker in order to produce a sound wave that has pressure amplitude 190 mPa at a distance of 6.75m away? Assume that the sound is spreading freely through room-temperature air of density 1.22 kg/m3. A milli-Pascal (mPa) is 10^-3 N/m2.arrow_forward
- An audio engineer takes decibel readings at a distance of r1= 11m and r2= 23m from a concert stage speaker during a soundcheck. When he is r1 from the speaker, the engineer registers a decibel level of b(beta)1= 101 dB on his loudness meter. 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 r1 from the speaker? b) how much power P, in watts, is coming from the speaker during the soundcheck at a distance r1? c) assuming that the speaker output does not change between the town measurements at r1 and r2, what sound intensity level b(beta)2, in decibels, will the loudness meter report when the engineer is at a distance r2 from the speaker?arrow_forwardSound is detected when a sound wave causes the eardrum to vibrate. Typically, the diameter of a human eardrum is around 8.4 mm. How much energy is delivered to your eardrum when someone whispers (20 dB) right next to your ear for 3.5 s?arrow_forward1) Due to the range of sound intensity we can perceive, we use a scale to describe the sound pressure or intensity of auditory stimuli, also known as what? 1) sound intensity level (SIL) 2) hertz (Hz) 3) decibels (dB) 4) kilohertz (kHz) 2) Factors that can decrease the perception of pain include: 1) focusing on a challenging activity. 2) humor. 3) release of endorphins. 4) all of the above.arrow_forward
- Two students hear the same sound and their eardrums receive the same power from the sound wave. The sound intensity at the eardrums of the first student is 0.79 W/m^2, while at the eardrums of the second student the sound intensity is 1.18 times greater. (A)What is the ratio of the diameter of the first student's eardrum to that of the second student? (B)If the diameter of the second student's eardrum 0.99 cm, how much acoustic power, in microwatts, is striking each of his (and the other student's) eardrums?arrow_forwardThe 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?arrow_forwardA skyrocket explodes 100 m above the ground (Fig. P14.24). Three observers are spaced 100 m apart, with the first (A) directly under the explosion. (a) What is the ratio of the sound intensity heard by observer A to that heard by observer B? (b) What is the ratio of the intensity heard by observer A to that heard by observer C? Figure P14.24arrow_forward
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