Worksheet: Sound Waves

In this worksheet, we will practice describing sound wave propagation, defining audible frequencies, and explaining the applications of reflections of sound waves.

Q1:

Which of the following sound waves is an example of ultrasound?

• A5,555 Hz
• B0.01 MHz
• C Hz
• D kHz
• E7.5 kHz

Q2:

Which of the following sound waves is an example of infrasound?

• A0.015 kHz
• B MHz
• C250 Hz
• D MHz
• E0.005 MHz

Q3:

A string on a violin is pushed by a bow and the string vibrates at a frequency of 440 Hz. The sound waves produced by the vibrating string have a wavelength of 0.75 m. What is the speed of the sound waves?

Q4:

A string on a guitar is pulled upward and released. The string vibrates, returning to the position from which it was released 196 times per second. What is the frequency of the sound wave produced by the string?

Q5:

A sound wave in an object alternately compresses and expands it in the direction that the wave travels. The sound has a wavelength of 0.48 m. What is the distance between the point of maximum compression and the point of maximum expansion in the object?

Q6:

Which of the following sound waves is within the human hearing range?

• A0.55 Hz
• B0.03 MHz
• C Hz
• D Hz
• E25 kHz

Q7:

A submarine’s sonar scanner uses sound waves that reflect from objects around the submarine. The submarine emits sound waves vertically downward and detects their reflection 6,000 milliseconds later. The sea beneath the submarine is 4,713 m deep. What is the speed of the sound waves? Answer to the nearest meter per second.

Q8:

A sound wave in air is shown in the diagram. What is the wavelength of the sound wave?

Q9:

An ultrasonic detector is used to find small air-filled cracks inside a concrete wall that is covered on one side with a thin layer of rubber, as shown in the diagram. The detector is placed in contact with the rubber surface, at the height of the crack. The rubber layer is 0.0025 m thick. The speed of sound in the concrete is 3 200 m/s and the speed of sound in the rubber is 1,600 m/s. The reflected sound from the crack in the wall is detected 0.045 s after the sound wave is emitted.

How many milliseconds pass before the reflected sound from the boundary between rubber and concrete is detected?

How deep into the concrete is the crack’s position?

Q10:

Which of the following statements most correctly describes how the density of a medium generally affects the speed at which sound waves propagate in the medium?

• AThere is no general relationship between the density of a medium and the speed at which sound waves propagate in the medium.
• BGenerally, the greater the density of a medium, the slower sound waves propagate in the medium.
• CGenerally, the greater the density of a medium, the faster sound waves propagate in the medium.

Q11:

The diagram shows a speaker cone moving back and forth with a frequency of 1 kHz. Sound waves propagate in the air in front of the speaker at a speed of 340 m/s. A vertical line downward from the point shows the equilibrium position of the speaker cone.

Which of the horizontal arrows starting at the horizontal position of has a length that most closely corresponds to the distance that a wave front initially at the horizontal position of would move through in a time of 1 millisecond?

• AV
• BIII
• CI
• DII
• EIV

Which of the horizontal arrows starting at the horizontal position of has a length that most closely corresponds to the distance that an air particle initially at the horizontal position of would move through in the first 0.25 milliseconds after the speaker cone started to move toward the right?

• AIV
• BV
• CI
• DII
• EIII

Which of the horizontal arrows starting at the horizontal position of P has a length that most closely corresponds to the displacement from the point that a typical air particle initially at the horizontal position of would have 1 millisecond after the speaker cone started to move toward the right?

• AII
• BNone of these lines
• CIV
• DI
• EIII