The power output of a certain public address speaker is 6.8 W. Suppose it broadcasts equally in all directions. At what distance (in cm) from the speaker would the sound be barely audible (B-120 dB)? (Answer in 2 decibal places)

The sound coming from 25 W spherical speaker has a decibel level of 90 dB. How far away is the speaker?

A speaker is producing spherically symmetric sounds with a total power of 88.5 W. If the speaker is located at the centre of a sphere with a radius of 2.20 m, what is the power received on a 1.70 m by 1.50 m area on the sphere? Give your answer in Watts to 2 decimal places.

A weather emergency siren is mounted on a tower, 153 m above the ground. On one hand, it would be a good idea to make the siren very loud so that it will warn as many people as possible. On the other hand, safety regulations prohibit the siren from exceeding an intensity level of 101 dB for workers standing on the ground directly below the siren. Assuming that the sound is uniformly emitted, what is the maximum power that the siren can put out? maximium power output: 3530 W Incorrect How far away from the base of the tower can a person be and still be able to hear the siren? Neglect any absorption of sound energy by the air; although, in reality, such absorption would be significant at long distances. maximum audible distance: 16733.2 Incorrect about us privacy policy terms of use help careers contact us

Problem 1: A speaker emits 40 W of 1000 Hz while at rest. a) If you receive 100 dB from the speaker, how far away from it are you? Answer: 17.8 m b) If you hear the speaker frequency to be 1100 Hz, what is the relative velocity between you and the speaker, and are you moving toward or away from it? Answer:|v| = 34.3– т S

according to the barometric measurements, the sound has a decibel level of 180 dB at a distance of 161 km. Assuming the intensity falls off as the inverse of the distance squared, what was the decibel level on the island 4800 km away?

A weather emergency siren is mounted on a tower, 153 m above the ground. On one hand, it would be a good idea to make the siren very loud so that it will warn as many people as possible. On the other hand, safety regulations prohibit the siren from exceeding an intensity level of 101 dB for workers standing on the ground directly below the siren. Assuming that the sound is uniformly emitted, what is the maximum power that the siren can put out? 79.432 maximium power output: W Incorrect How far away from the base of the tower can a person be and still be able to hear the siren? Neglect any absorption of sound energy by the air; although, in reality, such absorption would be significant at long distances. 13.636 x108 maximum audible distance: m Incorrect

Certain nuclear weapons produce infrasound waves with a frequency below the audible human range. How long will it take (in seconds) an infrasound wave of frequency 4.25 Hz and wavelength of 77.7 m to travel 1.50 km?

An interface is formed between a block of aluminium (with an acoustic impedance of 1.8 x 107 kg m2 s') and a block of copper (with an acoustic impedance of 4.6 x 107 kg m-2 s-1). Longitudinal sound waves travelling through the aluminium are normally incident on the boundary, and are partially reflected. a) What is the ratio of the amplitude of the reflected wave to that of the incident wave? Number b) What is the ratio of the amplitude of the transmitted wave to that of the incident wave? Number c) What percentage of the incident power is transmitted? Number d) What percentage of the incident power is reflected? Number % Ouit P Sove Questi

An 6 hour exposure to a sound intensity level of 95.0 dB may cause hearing damage. What energy in joules falls on a 0.900 cm diameter eardrum so exposed?