Multiple ChoiceA source emits a sound in the shape of a cone, as shown in the figure below. If you measure the intensity to be 100 W/m2 at a distance of 0.5 m, what is the power of the source?502views3comments
Multiple ChoiceA source emits sound spherically with a power of 2.2 × 104 W. What is the minimum distance away from this sound that would be considered safe (a volume of 150 dB or less)?454views3rank4comments
Multiple ChoiceSuppose an explosion can just be heard over normal conversation with an intensity of 1.0×10−6 W/m2 from 10 km away. At what distance from the explosion will the sound have an intensity that causes pain (10 W/m2)? Note that this calculation ignores absorption of sound energy by air and objects.312views1rank
Multiple ChoiceA speaker at a rock concert is causing you pain, so you reason the sound level must be 130 dB. The speaker is 11 m away from you. To what final distance from the speaker should you move for the sound level to reach a less-painful 105 dB? Keep in mind that we are ignoring absorption of sound energy by air and objects.300views
Multiple ChoiceA sound wave from a police siren has an intensity of 0.01 W/m2 at a certain distance. A second sound wave from an ambulance has a sound intensity level 8 dB greater than the police siren, when measured at the same distance. What is the sound intensity level (in dB) of the sound wave due to the ambulance? 241views7rank
Textbook Question(a) By what factor must the sound intensity be increased to raise the sound intensity level by 13.0 dB? (b) Explain why you don't need to know the original sound intensity434views
Textbook QuestionA baby's mouth is 30 cm from her father's ear and 1.50 m from her mother's ear. What is the difference between the sound intensity levels heard by the father and by the mother?339views
Textbook QuestionFor a person with normal hearing, the faintest sound that can be heard at a frequency of 400 Hz has a pressure amplitude of about 6.0 * 10-5 Pa. Calculate the (a) intensity631views1comments
Textbook QuestionYou live on a busy street, but as a music lover, you want to reduce the traffic noise. (b) If, instead, you reduce the intensity by half, what change (in dB) do you make in the sound intensity level?371views1rank
Textbook QuestionYou live on a busy street, but as a music lover, you want to reduce the traffic noise. (a) If you install special soundreflecting windows that reduce the sound intensity level (in dB) by 30 dB, by what fraction have you lowered the sound intensity 1in W>m2 2?472views1rank
Textbook QuestionA sound wave in air at 20°C has a frequency of 320 Hz and a displacement amplitude of 5.00 * 10-3 mm. For this sound wave calculate the (a) pressure amplitude (in Pa)709views
Textbook QuestionYou are trying to overhear a juicy conversation, but from your distance of 15.0 m, it sounds like only an average whisper of 20.0 dB. How close should you move to the chatterboxes for the sound level to be 60.0 dB?703views1rank
Textbook QuestionSound is detected when a sound wave causes the tympanic membrane (the eardrum) to vibrate. Typically, the diameter of this membrane is about 8.4 mm in humans. (a) How much energy is delivered to the eardrum each second when someone whispers (20 dB) a secret in your ear?874views
Textbook QuestionAssuming that the maximum displacement of the air molecules in a sound wave is about the same as that of the speaker cone that produces the sound (Fig. 16–46), estimate by how much a loudspeaker cone moves for a fairly loud (105 dB) sound of(b) 35 Hz. <IMAGE>102views
Textbook Question(I) What are the lowest and highest frequencies that an ear can detect when the sound level is 40 dB? (See Fig. 16–6.)94views
Textbook Question(II) Expensive amplifier A is rated at 280 W, while the more modest amplifier B is rated at 45 W.(b) What output wattage amp would sound about twice as loud as the 45-W amp?83views
Textbook Question(II) Your ears can accommodate a huge range of sound levels. What is the ratio of highest to lowest intensity at (a) 100 Hz, (b) 5000 Hz? (See Fig. 16–6.)98views
Textbook QuestionConsider a sound wave in air that has displacement amplitude 0.0200 mm. Calculate the pressure amplitude for frequencies of (a) 150 Hz; (b) 1500 Hz; (c) 15,000 Hz. In each case compare the result to the pain threshold, which is 30 Pa642views
Textbook QuestionWhat are the sound intensity levels for sound waves of intensity (a) 3.0 x 10⁻⁶ W/m²?330views
Textbook QuestionExample 16.1 (Section 16.1) showed that for sound waves in air with frequency 1000 Hz, a displacement amplitude of 1.2 * 10-8 m produces a pressure amplitude of 3.0 * 10-2 Pa. (a) What is the wavelength of these waves?310views
Textbook QuestionA loud factory machine produces sound having a displacement amplitude of 1.00 mm, but the frequency of this sound can be adjusted. In order to prevent ear damage to the workers, the maximum pressure amplitude of the sound waves is limited to 10.0 Pa. Under the conditions of this factory, the bulk modulus of air is 1.42 * 105 Pa. What is the highest-frequency sound to which this machine can be adjusted without exceeding the prescribed limit? Is this frequency audible to the workers?421views
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