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Sound & Hearing

Hearing is the ability to perceive sounds by detecting vibrations or changes in pressure through the ear. Sounds may be heard through solid, liquid or gaseous matter. Hearing is one of the traditional five senses. If someone has the inability to hear it is called deafness. Sound is the mechanical oscillating wave of pressure transmitted through some medium. It is composed of frequencies within the range of hearing.  

In vertebrates, hearing is performed by the auditory system. Vibrations of sound are detected by the ear and transduced into nerve impulses. These nerve impulses are then perceived by the brain. Similar to the sensation of touch, hearing requires sensitivity to the movement of molecules in the world outside the organism. Hearing and touch sensations are types of mechanosensation.

The human ear has three main components, the outer ear, the middle ear and the inner ear. The outer ear includes the visible part of the ear, the auditory canal and the eardrum. The middle ear consists of a small air filled chamber that is located behind the eardrum. Within this chamber are three small bones referred to collectively as the ossicles. The inner ear contains the cochlea. The cochlea is a spiral shaped fluid filled tube that is the organ of auditory transduction.

 

Categories within Sound & Hearing

Type of Interference and intensity level problems

1. There are two speakers at the front of the room. Each is outputting a 250Hz pure tone. For each of the following situations, will you hear constructive interference (a loud noise) or destructive interference (soft or no noise). Lambda represents the wavelength of the 250Hz tone. Choices: Constructive, Destructive. a. You are

Physics: Tuning fork, harmonics, transverse waves on a string

1. A tuning fork is sounded above a (narrow) resonating tube as in lab. The first resonant situation occurs when the water level is 0.08 m from the top of the tube, and the second when the level is at 0.24 m from the top. Let vsound = 340 m/s. a) Where is the water level for the third resonant point? b) What is the frequ

Frequency and wavelength of emitted sound wave

39. A violin string 17.8 cm long and fixed at both ends oscillates in it's n = 5 mode. The speed of waves on the string is 206 m/s, and the speed of sound in air is 348 m/s. What are (a) the frequency and (b) the wavelength of the emitted sound wave? 51. The A string of a violin is a little too tightly stretched. Beats at 4 p

Sound Waves: Standing Waves & Beats

1. Organ pipe A, with both ends open, has a fundamental frequency of 300 Hz. The third harmonic of organ pipe B, with one end open, has the same frequency as the second harmonic of pipe A. How long are (a) pipe A and (b) pipe B? 2. A tuning fork of unknown frequency makes 3.00 beats per second with a standard fork of frequenc

Pressure amplitude, frequency, wavelength, and speed of wave

1. The pressure in a traveling sound wave is given by the equation, as mentioned in the attachment. Find the (a) pressure amplitude, (b) frequency, (c) wavelength, and (d) speed of the wave. 2. Two sound waves, from two different sources with the same frequency, 540 Hz, travel in the same direction at 330 m/s. The sources are

Sound Waves: Beats, Beat Frequency

Each of three tuning forks, A, B, and C, has a slightly different frequency. When A and B are sounded together, they produce a beat frequency of 2 Hz. When A and C are sounded together, they produce a beat frequency of 5 Hz. What is the smallest possible beat frequency when B and C are sounded together?

Physics: Hearing & Sound Incident on the Eardrum

Hearing damage may occur when a person is exposed to a sound intensity level of 90.0 dB (relative to the threshold of human hearing) for a period of 9.00 hours. An eardrum has an area of 1.93 x 10-4 m2. How much sound energy is incident on the eardrum during this time?

Interference of Waves: Frequencies for Maximum Sound

A microphone is located on the line connecting two speakers that are 0.523 m apart and oscillating 180° out of phase. The microphone is 2.03 m from the midpoint of the two speakers. (a) What is the lowest frequency that produces an interference maximum at the microphone's location? (b) What is the next lowest frequency t

Frequency is measured for speakers

Two speakers separated by a distance of D = 4.30 m emit sound with opposite phase. A person listens from a location d1 = 2.90 m in front of one of the speakers. What is the lowest (nonzero) frequency that gives destructive interference in this case? .....Hz?

Determining Range of Lengths of Pipes

If you were to build a pipe organ with open-tube pipes spanning the range of human hearing (20 Hz to 20 kHz), what would be the range of the lengths of pipes required? Shortest pipe (in meters). Longest pipe (in meters).

Physics - Wave Motion

A steel cable with total length 30m and mass 100kg is connected to two poles. The tension in the cable is 3000N, and the wind makes the cable vibrate with a frequency of 2Hz. Calculate the wavelength of the resulting wave on the cable.

Destructive Interference of Sound Waves

Two adjacent sound sources each emit a frequency of 527[Hz] in air, where the velocity of sound is 349[m/s]. How much further back would source one have to move so that an observer in front of the two sources would hear no sound?

Linear Superposition and Interference Phenomena

The location of the speakers in this problem is what's throwing me off. Two speakers, one directly behind the other, are each generating a 245-Hz sound wave. What is the smallest separation distance between the speakers that will produce destructive interference at a listener standing in front of them? The speed of sound is

Tube filled with different media

The fundamental frequency of an open-open tube is 1500 Hz when the tube is filled with 0 degree Celsius helium. What is its frequency when filled with 0 degree Celsius air?

Sound waves travelling in air and solid

A man strikes a long aluminum rod at one end. Another man at the other end with his ear close to the rod, hears the sound of the blow twice (once through the air and once through the rod), with a 332 ms interval between them. How long is the rod?

Speed of Sound and Doppler Effect

The speed of sound in air is about 660miles/hour. A passenger train approaches an unguarded railroad crossing at a constant speed of 60 miles/hour and the locomotive sounds its horn which has a frequency of 400 Hz. [A]. What frequency does a listener standing near the crossing hear? [B]. If the train continues past the

Diffraction Horn Loudspeaker

Sound exits a diffraction horn loudspeaker through a rectangular opening like a small doorway. A person is sitting at an angle off to the side of a diffraction horn that has a width D of 0.060 m. The speed of sound is 343 m/s. This individual does not hear a sound wave that has a frequency of 8100 Hz. When she is sitting at

Sound travelling time through multiple mediums

An explosion occurs at the end of a pier. The sound reaches the other end of the pier by traveling through three media: air, fresh water and a slender metal handrail. The speeds of sound in air, water, and the handrail are 343, 1482, and 5040 m/s. The sound travels a distance of 125 m in each medium. a.) Which medium doe

distance between the speaker and observer

A loudspeaker is placed between two observers who are 120 m apart, along the line connecting them. If one observer records a sound level of 60.0 dB and the other records a sound level of 90 dB, how far is the speaker from each observer? (Hint: use the equation given in problem 17.28, page 538 which relates the difference between

Distance between two seats the tone of a horn cannot be heard

A row of seats is parallel to a stage at a distance of 8.7 m from it. At the center and front of the stage is a diffraction horn loudspeaker. This speaker sends out its sound through an opening that is like a small doorway with a width D of 7.5 cm. The speaker is playing a tone that has a frequency of 1.0 × 104 Hz. The speed

Superposition of sound waves

Two speakers are driven by the same oscillator whose frequency is f. They are located a distance d from each other on a vertical pole. A man walks straight toward the lower speaker in a direction perpendicular to the pole, as shown in Figure P14.10. (Note the answers must be in all variables) (a) How many times will he hea

Sound intensity, Speed of waves on the string

1. The intensity of sound 20 meters from a race car is 0.0100 W/m^2. (A) What is the sound intensity level in dB? (B) What would the intensity (in W/m^2) be at a distance 80 m from the car? Find the corresponding intensity level in dB. 2. Suppose a violin player touches the "A" string 1/3 of the distance from the end, which

The Beat Heard by a Bat

(See attached file for full problem description) --- The Beat Heard by a Bat A bat flies toward a wall, emitting a steady sound with a frequency of 25.0 . This bat hears its own sound plus the sound reflected by the wall. Part A How fast should the bat fly, , to hear a beat frequency of 220 ? Take the speed of soun

Harmonics of a Piano

(See attached file for full problem description with proper symbols and diagram) --- Harmonics of a Piano Wire A piano tuner stretches a steel piano wire with a tension of 800 N. The steel wire has a length of 0.400 m and a mass of 3.00 g. Part A: What is the frequency f1 of the string's fundamental mode of vibration?

Standing Waves

(See attached file for full problem description and figures) --- 21.8 The figure shows a standing wave oscillating at 100 Hz on a string. Part A : What is the wave speed? 21.5 A 40-cm-long tube has a 40-cm-long insert that can be pulled in and out. A vibrating tuning fork is held next to the tube. As the ins

Ocean Depth

A sailor strikes the side of his ship just below the surface of the sea. He hears the echo of the wave reflected from the ocean floor directly 3.85 s later. How deep is the ocean at this point?

Sound Waves

A steel guitar string has a length of 74 cm and thickness of 0.37 mm. It is under 35N tension. Calculate the wave speed in the string. The density of steel rho=7.84 x 10^3 kg/m^3.

Calculating the Frequency of Sound

A train is approaching a station and blows its horn with a frequency of 200hz. If the train has a speed of 25 m/s and the speed of sound is 350 m/s, what is the frequency of sound heard by the people standing on the platform a. 190hz b. 186hz c. 210 hz d. 200hz

How far is the speaker from each observer?

A loudspeaker is placed between two observers who are 120m apart along the line connecting them. If one observer records a sound level of 60dB and the other records a sound level of 90dB, how far is the speaker from each observer?

Tuning Fork and Its Vibrations

If the handle of a tuning fork is held solidly against a table, the sound from the tuning fork becomes louder. Why? How will this affect the length of time the fork keeps vibrating? Please explain. This is a CONCEPTUAL question.