The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10-10 W/m2.What is the intensity level in dB? The threshold of human hearing is 1.0 × 10-12 W/m2.

A) 18 dB B) 23 dB C) 28 dB D) 32 dB A) 18 dB B) 23 dB C) 28 dB D) 32 dB

What is the intensity level in decibels of a sound with intensity 10-3 W/m2? The threshold of human hearing is 1.0 × 10-12 W/m2.

A) 30 dB B) 60 dB C) 90 dB D) 96 dB A) 30 dB B) 60 dB C) 90 dB D) 96 dB

Exam 21: Mechanical Waves

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10^-10 W/m².What is the intensity level in dB? The threshold of human hearing is 1.0 × 10^-12 W/m².

(Multiple Choice)

4.9/5

(78)

Question 21

A barking dog delivers about 1.0 mW of power,which is assumed to be uniformly distributed in all directions.What is the intensity level in decibels at a distance 5.00 m from the dog? The threshold of human hearing is 1.0 × 10^-12 W/m².

(Multiple Choice)

4.9/5

(90)

Question 22

A 25-g string is stretched with a tension of 43 N between two fixed points 12 m apart.What is the frequency of the second harmonic?

(Multiple Choice)

5.0/5

(77)

Question 23

Suppose that a sound source is emitting waves uniformly in all directions.If you move to a point twice as far away from the source,the frequency of the sound will be

(Multiple Choice)

4.9/5

(80)

Question 24

The wavelengths of the sounds produced by two horns are 6.0 m and 7.0 m,respectively.What beat frequency is heard when the horns are sounded on a day when the speed of sound is 340 m/s?

(Multiple Choice)

4.8/5

(76)

Question 25

Which one of the curves shown in the figure best represents the variation of wave speed v as a function of tension for transverse waves on a stretched string?

(Multiple Choice)

4.7/5

(69)

Question 26

By how many decibels does the intensity level of a sound increase when you triple the intensity of a source of sound?

(Multiple Choice)

4.8/5

(76)

Question 27

What is the intensity level in decibels of a sound with intensity 10^-3 W/m²? The threshold of human hearing is 1.0 × 10^-12 W/m².

(Multiple Choice)

4.9/5

(75)

Question 28

A police car has an 800-Hz siren.It is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s.The car approaches and passes an observer who is standing along the roadside.What change of frequency does the observer hear?

(Multiple Choice)

5.0/5

(88)

Question 29

A fisherman fishing from a pier observes that the float on his line bobs up and down,taking 2.4 s to move from its highest point to its lowest point.He also estimates that the distance between adjacent wave crests is 48 m.What is the speed of the waves going past the pier?

(Multiple Choice)

4.8/5

(92)

Question 30

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10^-10 W/m².What is the power emitted by the source?

(Multiple Choice)

4.8/5

(92)

Question 31

A long-term exposure to the sound of a riveting machine can cause your threshold of hearing to shift from 0 dB to 30 dB.What is the sound intensity of a 30-dB sound? The normal lowest detectable intensity is 1.0 × 10^-12 W/m².

(Short Answer)

4.8/5

(62)

Question 32

Sound A has a high pitch and sound B has a low pitch.Which of the following statements about these two sounds are correct? (There could be more than one correct choice.)

(Multiple Choice)

4.8/5

(84)

Question 33

One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz,and the next higher harmonic has a frequency of 576 Hz.What is the fundamental frequency of the air column in this tube?

(Multiple Choice)

5.0/5

(79)

Question 34

A certain factory whistle can be heard up to a distance of 9.8 km.Assuming that the acoustic output of the whistle is uniform in all directions,at what distance from the factory is the intensity level of the whistle sound equal to 25 dB? The threshold of human hearing is 1.0 × 10^-12 W/m².

(Multiple Choice)

4.9/5

(79)

Question 35

A string of mass m is under tension,and the speed of a wave in the string is v.What will be the speed of a wave in the string if the mass of the string is increased to 2m but with no change in the length or tension?

(Multiple Choice)

4.9/5

(73)

Question 36

Two strings both vibrate at exactly 819 Hz.The tension in one of them is then increased slightly.As a result,six beats per second are heard when both strings vibrate.What is the new frequency of the string that was tightened?

(Multiple Choice)

4.8/5

(76)

Question 37

The vertical displacement y(x,t)of a horizontal string aligned along the x-axis is given by the equation y(x,t)= (6.00 mm)cos[(3.25 m^-1)x - (7.22 s^-1)t].What are the (a)wavelength and (b)period of this wave?

(Short Answer)

5.0/5

(80)

Question 38

Two in-phase loudspeakers are some distance apart.They emit sound with a frequency of 536 Hz.A microphone is moved between the speakers along the line joining the two speakers with a constant speed of 1.60 m/s.What beat frequency is observed? The speed of sound in air is 343 m/s.

(Multiple Choice)

4.9/5

(90)

Question 39

You are driving along a highway at 25 m/s when you hear the siren of an emergency vehicle traveling at constant speed in the opposite direction on the other side of the highway.When the vehicle is approaching you,you hear the frequency of the siren as 2380 Hz,but when it is past you the frequency becomes 1680 Hz.What is the speed of the vehicle? The speed of sound in air is 343 m/s.

(Multiple Choice)

4.8/5

(84)

Question 40

Showing 21 - 40 of 155

Exam 21: Mechanical Waves

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10-10 W/m2.What is the intensity level in dB? The threshold of human hearing is 1.0 × 10-12 W/m2.

A barking dog delivers about 1.0 mW of power,which is assumed to be uniformly distributed in all directions.What is the intensity level in decibels at a distance 5.00 m from the dog? The threshold of human hearing is 1.0 × 10-12 W/m2.

A 25-g string is stretched with a tension of 43 N between two fixed points 12 m apart.What is the frequency of the second harmonic?

Suppose that a sound source is emitting waves uniformly in all directions.If you move to a point twice as far away from the source,the frequency of the sound will be

The wavelengths of the sounds produced by two horns are 6.0 m and 7.0 m,respectively.What beat frequency is heard when the horns are sounded on a day when the speed of sound is 340 m/s?

Which one of the curves shown in the figure best represents the variation of wave speed v as a function of tension for transverse waves on a stretched string?

By how many decibels does the intensity level of a sound increase when you triple the intensity of a source of sound?

What is the intensity level in decibels of a sound with intensity 10-3 W/m2? The threshold of human hearing is 1.0 × 10-12 W/m2.

A police car has an 800-Hz siren.It is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s.The car approaches and passes an observer who is standing along the roadside.What change of frequency does the observer hear?

A fisherman fishing from a pier observes that the float on his line bobs up and down,taking 2.4 s to move from its highest point to its lowest point.He also estimates that the distance between adjacent wave crests is 48 m.What is the speed of the waves going past the pier?

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10-10 W/m2.What is the power emitted by the source?

A long-term exposure to the sound of a riveting machine can cause your threshold of hearing to shift from 0 dB to 30 dB.What is the sound intensity of a 30-dB sound? The normal lowest detectable intensity is 1.0 × 10-12 W/m2.

Sound A has a high pitch and sound B has a low pitch.Which of the following statements about these two sounds are correct? (There could be more than one correct choice.)

One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz,and the next higher harmonic has a frequency of 576 Hz.What is the fundamental frequency of the air column in this tube?

A certain factory whistle can be heard up to a distance of 9.8 km.Assuming that the acoustic output of the whistle is uniform in all directions,at what distance from the factory is the intensity level of the whistle sound equal to 25 dB? The threshold of human hearing is 1.0 × 10-12 W/m2.

A string of mass m is under tension,and the speed of a wave in the string is v.What will be the speed of a wave in the string if the mass of the string is increased to 2m but with no change in the length or tension?

Two strings both vibrate at exactly 819 Hz.The tension in one of them is then increased slightly.As a result,six beats per second are heard when both strings vibrate.What is the new frequency of the string that was tightened?

The vertical displacement y(x,t)of a horizontal string aligned along the x-axis is given by the equation y(x,t)= (6.00 mm)cos[(3.25 m-1)x - (7.22 s-1)t].What are the (a)wavelength and (b)period of this wave?

Two in-phase loudspeakers are some distance apart.They emit sound with a frequency of 536 Hz.A microphone is moved between the speakers along the line joining the two speakers with a constant speed of 1.60 m/s.What beat frequency is observed? The speed of sound in air is 343 m/s.

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

First Law of Thermodynamics

Second Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Magnetism

Electromagnetic Induction

Vibrational Motion

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10^-10 W/m².What is the intensity level in dB? The threshold of human hearing is 1.0 × 10^-12 W/m².

A barking dog delivers about 1.0 mW of power,which is assumed to be uniformly distributed in all directions.What is the intensity level in decibels at a distance 5.00 m from the dog? The threshold of human hearing is 1.0 × 10^-12 W/m².

What is the intensity level in decibels of a sound with intensity 10^-3 W/m²? The threshold of human hearing is 1.0 × 10^-12 W/m².

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10^-10 W/m².What is the power emitted by the source?

A long-term exposure to the sound of a riveting machine can cause your threshold of hearing to shift from 0 dB to 30 dB.What is the sound intensity of a 30-dB sound? The normal lowest detectable intensity is 1.0 × 10^-12 W/m².

A certain factory whistle can be heard up to a distance of 9.8 km.Assuming that the acoustic output of the whistle is uniform in all directions,at what distance from the factory is the intensity level of the whistle sound equal to 25 dB? The threshold of human hearing is 1.0 × 10^-12 W/m².

The vertical displacement y(x,t)of a horizontal string aligned along the x-axis is given by the equation y(x,t)= (6.00 mm)cos[(3.25 m^-1)x - (7.22 s^-1)t].What are the (a)wavelength and (b)period of this wave?