Question 1

The Young's modulus of aluminum is 6.90 × 1010 N/m2. If the density of aluminum is 2,700 kg/m3, then what is the speed of longitudinal waves along a thin aluminum rod?

Accepted Answer

A)  6,360 m/s 
B)  6,020 m/s 
C)  5,750 m/s 
D)  5,060 m/s 
E)  4,850 m/s 
A)  6,360 m/s 
B)  6,020 m/s 
C)  5,750 m/s 
D)  5,060 m/s 
E)  4,850 m/s

Question 2

A 30.0 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the frequency of the second mode of vibration?

Accepted Answer

A)  900 Hz 
B)  828 Hz 
C)  750 Hz 
D)  721 Hz 
E)  650 Hz 
A)  900 Hz 
B)  828 Hz 
C)  750 Hz 
D)  721 Hz 
E)  650 Hz

Question 3

A 30.0 cm long brass rod is suspended at the ends by long strings. The rod is struck at one end parallel to the rod and causes the rod to vibrate longitudinally with the ends free. (Y = 9.00 × 1010 N/m2, density = 8,470 kg/m3.) Assuming the rod vibrates in its fundamental mode, the frequency of the vibration is

Accepted Answer

A)  5,430 Hz. 
B)  5,020 Hz. 
C)  4,760 Hz. 
D)  4,500 Hz. 
E)  3,950 Hz. 
A)  5,430 Hz. 
B)  5,020 Hz. 
C)  4,760 Hz. 
D)  4,500 Hz. 
E)  3,950 Hz.

Question 4

A string with a mass per length of 2.00 g/m is stretched with a force of 120 N between two points that are 0.400 m apart. The fundamental frequency of the stretched string is in tune with the frequency of the second mode of an organ pipe filled with air and open at both ends. The speed of sound in air at 0°C is 331 m/s. What is the length of the organ pipe?

Accepted Answer

A)  225 cm 
B)  175 cm 
C)  125 cm 
D)  108 cm 
E)  95.0 cm 
A)  225 cm 
B)  175 cm 
C)  125 cm 
D)  108 cm 
E)  95.0 cm

Question 5

A 50 cm long organ pipe is filled with air and is open at both ends. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the second mode?

Accepted Answer

A)  50 cm 
B)  75 cm 
C)  90 cm 
D)  40 cm 
E)  63 cm 
A)  50 cm 
B)  75 cm 
C)  90 cm 
D)  40 cm 
E)  63 cm

Question 6

If on a given day the speed of sound increases by 1.5% between 8:00am and 11:00am, and if the temperature at 8:00am was 21°C, what was the temperature at 11:00am?

Accepted Answer

A)  21.6°C 
B)  21.3°C 
C)  25.4°C 
D)  29.9°C 
A)  21.6°C 
B)  21.3°C 
C)  25.4°C 
D)  29.9°C

Question 7

A 20 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the fundamental mode?

Accepted Answer

A)  40 cm 
B)  60 cm 
C)  80 cm 
D)  43 cm 
E)  75 cm 
A)  40 cm 
B)  60 cm 
C)  80 cm 
D)  43 cm 
E)  75 cm

Question 8

A 20.0 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the frequency of the third mode of vibration?

Accepted Answer

A)  2,900 Hz 
B)  2,480 Hz 
C)  2,070 Hz 
D)  1,660 Hz 
E)  1,240 Hz 
A)  2,900 Hz 
B)  2,480 Hz 
C)  2,070 Hz 
D)  1,660 Hz 
E)  1,240 Hz

Question 9

A 60.0 cm long brass rod is suspended at the ends by long strings. The rod is struck at one end parallel to the rod and causes the rod to vibrate longitudinally with the ends free. (Y = 9.00 × 1010 N/m2, density = 8,470 kg/m3.) Assuming the rod vibrates in its fundamental mode, the frequency of the vibration is

Accepted Answer

A)  3,790 Hz. 
B)  3,540 Hz. 
C)  3,120 Hz. 
D)  2,720 Hz. 
E)  2,140 Hz. 
A)  3,790 Hz. 
B)  3,540 Hz. 
C)  3,120 Hz. 
D)  2,720 Hz. 
E)  2,140 Hz.

Question 10

A 60.0 cm long organ pipe is filled with air and is open at both ends. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the fundamental mode?

Accepted Answer

A)  115 cm 
B)  120 cm 
C)  131 cm 
D)  142 cm 
E)  167 cm 
A)  115 cm 
B)  120 cm 
C)  131 cm 
D)  142 cm 
E)  167 cm

Question 11

The temperature is observed to decrease from 32°C to 23°C during the evening of a very hot day. What is the relative change in the speed of sound over this time interval?

Accepted Answer

A)  −15% 
B)  −28% 
C)  −1.5% 
D)  −3% 
A)  −15% 
B)  −28% 
C)  −1.5% 
D)  −3%

Question 12

An organ pipe is 60.0 cm long and is open at one end and closed at the other. The frequency of the third mode is 300 Hz higher than the frequency of the second mode. What is the speed of sound?

Accepted Answer

A)  280 m/s 
B)  300 m/s 
C)  320 m/s 
D)  340 m/s 
E)  360 m/s 
A)  280 m/s 
B)  300 m/s 
C)  320 m/s 
D)  340 m/s 
E)  360 m/s

Question 13

Two organ pipes, open at both ends, are meant to be the same length, but apparently they are not. When played simultaneously the beat frequency heard is 2.4 Hz. If the fundamental frequency of the first pipe is 228 Hz, by what fraction is the first pipe different in length than the second?

Accepted Answer

A)  2% 
B)  −2% 
C)  −1% 
D)  Not enough information 
E)  1% 
A)  2% 
B)  −2% 
C)  −1% 
D)  Not enough information 
E)  1%

Question 14

A sound wave in helium has an intensity of 1.00 × 10−3 W/m2. The density of helium is 0.179 kg/m3 and the speed of sound in helium is 965 m/s. The pressure amplitude of the sound wave is

Accepted Answer

A)  0.682 N/m2. 
B)  0.588 N/m2. 
C)  0.476 N/m2. 
D)  0.345 N/m2. 
E)  0.276 N/m2. 
A)  0.682 N/m2. 
B)  0.588 N/m2. 
C)  0.476 N/m2. 
D)  0.345 N/m2. 
E)  0.276 N/m2.

Question 15

The speed of sound in helium is 965 m/s. If the density of helium is 0.179 kg/m3, then what is the bulk modulus of helium?

Accepted Answer

A)  2.70 × 105 N/m2 
B)  2.40 × 105 N/m2 
C)  2.20 × 105 N/m2 
D)  1.67 × 105 N/m2 
E)  1.56 × 105 N/m2 
A)  2.70 × 105 N/m2 
B)  2.40 × 105 N/m2 
C)  2.20 × 105 N/m2 
D)  1.67 × 105 N/m2 
E)  1.56 × 105 N/m2

Question 16

A guitar string with a tension of 150 N is played together with a tuning fork whose frequency is 256 Hz, and beats of 2 Hz are heard. Assuming the guitar string is higher in frequency than the tuning fork, to what new tension should the guitar string be adjusted for the string and tuning fork to have the same frequency?

Accepted Answer

A)  148 N 
B)  149 N 
C)  151 N 
D)  152 N 
E)  The length of the string must be given in order to solve this problem. 
A)  148 N 
B)  149 N 
C)  151 N 
D)  152 N 
E)  The length of the string must be given in order to solve this problem.

Question 17

A 30 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the third mode of vibration?

Accepted Answer

A)  48 cm 
B)  36 cm 
C)  30 cm 
D)  24 cm 
E)  12 cm 
A)  48 cm 
B)  36 cm 
C)  30 cm 
D)  24 cm 
E)  12 cm

Question 18

An ambulance is generating a siren sound at a frequency of 2,400 Hz. The speed of sound is 345.0 m/s. The observer is traveling at a velocity of 24.00 m/s toward the ambulance and the ambulance is traveling at a velocity of 24.00 m/s away the observer. What is the frequency of the siren perceived by the observer?

Accepted Answer

A)  2,448 Hz 
B)  2,424 Hz 
C)  2,400 Hz 
D)  2,376 Hz 
E)  2,352 Hz 
A)  2,448 Hz 
B)  2,424 Hz 
C)  2,400 Hz 
D)  2,376 Hz 
E)  2,352 Hz

Question 19

A sound wave radiates from a source uniformly in all directions. If the power of the sound source is 200 watts, then the intensity level of the sound wave 100 m from the source is

Accepted Answer

A)  98.5 dB. 
B)  92.0 dB. 
C)  91.5 dB. 
D)  89.6 dB. 
E)  88.3 dB. 
A)  98.5 dB. 
B)  92.0 dB. 
C)  91.5 dB. 
D)  89.6 dB. 
E)  88.3 dB.

Question 20

An organ pipe is open at both ends. The frequency of the fourth mode is 316 Hz higher than the frequency of the third mode. If the speed of sound is 340 m/s, then what is the length of the organ pipe?

Accepted Answer

A)  53.8 cm 
B)  59.8 cm 
C)  60.3 cm 
D)  62.8 cm 
E)  64.7 cm 
A)  53.8 cm 
B)  59.8 cm 
C)  60.3 cm 
D)  62.8 cm 
E)  64.7 cm

Exam 12: Sound

The Young's modulus of aluminum is 6.90 × 1010 N/m2. If the density of aluminum is 2,700 kg/m3, then what is the speed of longitudinal waves along a thin aluminum rod?

A 30.0 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the frequency of the second mode of vibration?

A 50 cm long organ pipe is filled with air and is open at both ends. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the second mode?

If on a given day the speed of sound increases by 1.5% between 8:00am and 11:00am, and if the temperature at 8:00am was 21°C, what was the temperature at 11:00am?

A 20 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the fundamental mode?

A 20.0 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the frequency of the third mode of vibration?

A 60.0 cm long organ pipe is filled with air and is open at both ends. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the fundamental mode?

The temperature is observed to decrease from 32°C to 23°C during the evening of a very hot day. What is the relative change in the speed of sound over this time interval?

An organ pipe is 60.0 cm long and is open at one end and closed at the other. The frequency of the third mode is 300 Hz higher than the frequency of the second mode. What is the speed of sound?

Two organ pipes, open at both ends, are meant to be the same length, but apparently they are not. When played simultaneously the beat frequency heard is 2.4 Hz. If the fundamental frequency of the first pipe is 228 Hz, by what fraction is the first pipe different in length than the second?

A sound wave in helium has an intensity of 1.00 × 10−3 W/m2. The density of helium is 0.179 kg/m3 and the speed of sound in helium is 965 m/s. The pressure amplitude of the sound wave is

The speed of sound in helium is 965 m/s. If the density of helium is 0.179 kg/m3, then what is the bulk modulus of helium?

A 30 cm long organ pipe is filled with air and is open at one end and closed at the other. The speed of sound in air at 0°C is 331 m/s. What is the wavelength of the third mode of vibration?

A sound wave radiates from a source uniformly in all directions. If the power of the sound source is 200 watts, then the intensity level of the sound wave 100 m from the source is

An organ pipe is open at both ends. The frequency of the fourth mode is 316 Hz higher than the frequency of the third mode. If the speed of sound is 340 m/s, then what is the length of the organ pipe?

Introduction

Motion Along a Line

Motion in a Plane

Force and Newtons Laws of Motion

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Magnetic Forces and Fields

Electromagnetic Induction

Alternating Current

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

The Young's modulus of aluminum is 6.90 × 10¹⁰ N/m². If the density of aluminum is 2,700 kg/m³, then what is the speed of longitudinal waves along a thin aluminum rod?

A sound wave in helium has an intensity of 1.00 × 10⁻³ W/m². The density of helium is 0.179 kg/m³ and the speed of sound in helium is 965 m/s. The pressure amplitude of the sound wave is

The speed of sound in helium is 965 m/s. If the density of helium is 0.179 kg/m³, then what is the bulk modulus of helium?