(a) Ear trumpets were never very common, but they did aid people with hearing losses by gathering sound over a large area and concentrating it on the smaller area of the eardrum. What decibel increase does an ear trumpet produce if its sound gathering area is 900 cm2 and the area of the eardrum is 0.500 cm2 , but the trumpet only has an efficiency of 5.00% in transmitting the sound to the eardrum? (b) Comment on the usefulness of the decibel increase found in part (a).

If a machine produces sound with an intensity level of 97.1 dB, what would its intensity level have to be to reduce the intensity by a factor of 2.40?

If the sound level of one barking dog is 40 dB, estimate the sound level of 2 dogs barking simultaneously in the same place.

The earplug can reduce the sound level to about 18 decibels (dB). What percentage reduction is this intensity?

A point source emits sound waves with a power oulput of 288 watts. What is the sound level (in dB) at a distance of 69.7 m? (Answer in 2 decimal places)

A violinist pulls a bow with a force of 0.6 N, at a speed of 0.5 m/s, playing an A tone, with a frequency of 440 Hz, which is perceived by a listener who is at a distance of 35 m with a volume of 60 dB. What is the efficiency of the conversion of mechanical energy into energy of sound?

With a sound level meter, you measure the sound pressure level to 95 dB. A sound source is a work machine that is on a hard surface, i.e. it can be thought of as sending sound to the surface of a hemisphere. The device is 20 m away from you. Calculate the power of the sound produced by the device in watts to one decimal place.   Also Calculate the sound pressure level to the nearest decibel if your distance from the device doubles.

A sound wave traveling through water must vibrate approximately 1000 times more mass than one traveling through air, Calculate the ratio of the vibration amplitude of sound in air and that in water, assuming equal frequency and energy of vibration.

What is the loudness level of a sound wave delivering 40 watts of power that has traveled 8 meters? (b) What is the intensity of the sound wave after traveling 20 meters?

Sound is more effectively transmitted into a stethoscope by direct contact rather than through the air, and it is further intensified by being concentrated on the smaller area of the eardrum. It is reasonable to assume that sound is transmitted into a stethoscope 100 times as effectively compared with transmission though the air. What, then, is the gain in decibels produced by a stethoscope that has a sound gathering area of 15.0 cm2 , and concentrates the sound onto two eardrums with a total area of 0.900 cm2 with an efficiency of 40.0% ?