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Intensity and Power Determine the intensity of the 1000 Hz sound wave in Example 15-2. Assuming that a human eardrum has a radius of approximately 0.75 cm, determine how much power is delivered to the ear by such a wave.
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Electrical Engineering
Interference Pattern Two speakers (treated as point sources) are placed 2.0 m apart and are emitting sound waves with the same amplitude and phase; the wavelength is 1.0 m. Sketch the interference pattern, and identify points of constructive and destructive interference.
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Electrical Engineering
Adding Sound Levels In this example we wish to explore how to determine the sound level due to multiple sound sources. We can see in Table 15-4 that if we are 1 m away from a lawnmower, the sound level is 107 dB, while if we are 1 m away from a chainsaw, the sound level is 110 dB. Suppose you are 1 m away from both a lawnmower and a chainsaw. What are the resultant sound intensity and sound level?
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Electrical Engineering
Concert Sound Level You are at a concert where the sound intensity measures 3.00 W/m2. What is the sound level in decibels? Should you be concerned about your hearing?
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Electrical Engineering
Speaker Power Assume that you are 50.m from the stage at a concert where the sound intensity is 0.30 W/m2. How much power are the speakers radiating, assuming that they direct their sound output toward the audience such that the sound intensity in that direction is 8 times as great as if the speakers were isotropic point sources?
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Electrical Engineering
The Doppler Effect A high-speed train travelling at 250 km/h blows its whistle as it approaches a level crossing. The whistle has a frequency of 660 Hz. What frequency would be perceived by someone standing at the crossing as the train? (a) approaches the crossing? (b) moves away from the crossing?
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Electrical Engineering
Suppose a bat is flying at 6.00 m/s chasing a moth that is flying at 4.00 m/s directly away from the bat. If the bat is emitting echolocation cries at 82.0 kHz, at what frequency will the moth hear the cries?
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Electrical Engineering
Pulse on a String A pulse is travelling from left to right with a speed of 2.0 m/s along a stretched string. Figure 14-17 shows the waveform of the pulse when t = 1.0 s. Fig.14-17 A displacement versus position plot of a pulse at t 5 1.0 s, travelling in the positive x-direction. Find the displacements of the string elements at x = 0.0 m and x = 5.0 m at this time. Where was the peak of the pulse at t=0.0 s? Where will the peak of the pulse be 5.0 s later?
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Electrical Engineering
