Solution Fo Assignmet

5/24/2018 Solution Fo Assignmet

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Part ABased on the information presented in the introduction of this problem, what is a sound wave?

A. Propagation of sound particles that are different from the particles that comprise the medium

B. Propagation of energy that does not require a medium

C. Propagation of pressure fluctuations in a medium

D. Propagation of energy that passes through empty spaces between the particles that comprise the medium

C. Propagation of pressure fluctuations in a medium

Part BHaving established that a sound wave corresponds to pressure fluctuations in the medium, what can you conclu

about the direction in which such pressure fluctuations travel?

A. The direction of motion of pressure fluctuations is independent of the direction of motion of the sound wave

B. Pressure fluctuations travel perpendicularly to the direction of propagation of the sound wave.

C. Pressure fluctuations travel along the direction of propagation of the sound wave.

C. Pressure fluctuations travel along the direction of propagation of the sound wave.Part CDoes air play a role in the propagation of the human voice from one end of a lecture hall to the other?

A. yes

B. no

A. yes

Part DThe graphs shown here represent pressure variation versus time recorded by a microphone. Which could corres

to a sound wave?

Enter the letters of all the correct answers in alphabetical order. Do not use commas. For example, if you think a

three graphs could represent sound waves, enter ABC.

BC
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Part E

Given by the problem:Speed of sound "v" (m/s): 344

Period of wave "T" (s):0.001

Solution:Answer "f, " (Hz, m):

1000,0.344

Remember to use proper units and significant figures in your answer

The next graph shows a sound wave consisting of a sinu

displacement of air particles versus time, as recorded at a fixed location. For sinusoidal waves, it is possible to

identify a specific frequency (rate of oscillation) and wavelength (distance in space corresponding to one comple

cycle).Taking the speed of sound in air to be 344 m/s, what are the frequency f and the wavelength lambda of the sou

wave shown in the graph?

Express your answers in, respectively, hertz and meters to three significant figures. Separate the two answers w

comma.

The velocity of a wave equals its frequency times the wavelength:

v = f

V is given as 344m/s and T is shown by the graph to be 10-3s = 0.001s. Since f = 1/T, f = 1/0.001 = 1000HzTherefore:

v = f

344 = 1000
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= 0.344So the answer is:

1000,0.344Note: pay attention to the labellings of the axes. For this problem, the x-axis was labeled as t(s), so its represe

period, not

Part FA certain sound is recorded by a microphone. The same microphone then detects a second sound, which is iden

to the first one except that the amplitude of the pressure fluctuations is larger. In addition to the larger amplitu

what distinguishes the second sound from the first one?

A. It is perceived as higher in pitch.

B. It is perceived as louder.

C. It has a higher frequency.

D. It has a longer wavelength.

B. It is perceived as louder.Part GA certain sound is recorded by a microphone. A second sound that has twice the frequency is detected by the sa

microphone. In addition to the higher frequency, what distinguishes the second sound from the first one?


B. It is perceived as louder.

C. It has a higher amplitude.

D. It has a longer wavelength.


Part HWhat varies between two tones that are different in timbre, that is, two tones that have the same fundamental

frequency but are produced, say, by different musical instruments?

Note that Figures (b) and (c) from Part D could represent tones with different timbre.

A. the pitch

B. the harmonic content

C. nothing

B. the harmonic content

The Decibel ScalePart AWhat is the sound intensity level , in decibels, of a sound wave whose intensity is 10 times the reference intens

(i.e., I = 10I0)?

Express the sound intensity numerically to the nearest integer.

Just follow the formula:
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= 10log(I / I0)

= 10log(10 / 1)

= 10log(10)

= 10 dB

10 dBPart BWhat is the sound intensity level , in decibels, of a sound wave whose intensity is 100 times the reference inten

(i.e., I = 100I0)?

Express the sound intensity numerically to the nearest integer.

Just follow the formula:

= 10log(I / I0)

= 10log(100 / 1)

= 10log(100)

= 20 dB

20 dBPart COne often needs to compute the change in decibels corresponding to a change in the physical intensity measur

units of power per unit area. Take f to be the factor of increase of the physical intensity.

Calculate the change in decibels (2, 4, and 8) corresponding to f = 2, f = 4, and f = 8.

To find the increase take I0in the general formula to be the initial intensity and then take I to be the factor of

increase: I=fI0. Then, log(I / I0) = log(f) and the change in intensity measured in decibels is 10log(f).

The answer is:

3,6,9 dB

3,6,9 dB


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= 17 cm

= v/f

=

= 13.1923 x 10-6m

= 1.31923 x 10-5


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d = vt

t =

=

= 1.0897 s

d = vt

t =

=

= 4.95626 s


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Answer:

H22 (343 m/s) (

+ 3.1 )h + ( 3.1)^2 (343)^2 = 0

H2

26136.6 h + 1.131 x 10^6 = 0

H can be = 43.5 = 44 m and 26092 m

So final answer will be

= 43.5 = 44 m


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L = K log I

2L = k log In

2(log I) = log In

In = I^2

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Solution Fo Assignmet