Describing Sound Waves

Question 1

What is the definition of frequency in sound waves?

Answer 1

The number of cycles that occur in 1 second.

Measured in Hertz (Hz).

Question 2

What is the typical frequency range for audible sound?

Answer 2

20 Hz - 20,000 Hz (20 kHz).

Sounds below 20 Hz are considered infrasound, and above 20 kHz are considered ultrasound.

Question 3

What is the formula for calculating period?

Answer 3

Period = 1/frequency.

Period is measured in seconds.

Question 4

What is the typical value for the period of sound waves?

Answer 4

0.06 - 0.5 microseconds (us).

This represents the duration of one complete cycle.

Question 5

Define amplitude in the context of sound waves.

Answer 5

The ‘bigness’ of a wave; the difference between the maximum or minimum value and the average value of the acoustic variable.

Peak-to-peak amplitude is the difference between maximum and minimum values.

Question 6

What is the relationship between power and intensity in sound waves?

Answer 6

Intensity = Power/Area.

Intensity is directly related to amplitude.

Question 7

What are the units for measuring sound intensity?

Answer 7

Watts/cm², dB.

Decibels (dB) are a logarithmic measure of sound intensity.

Question 8

What is the formula for calculating speed of sound?

Answer 8

Speed = frequency x wavelength.

Speed is measured in meters per second (m/s).

Question 9

What is the typical speed of sound in soft tissue?

Answer 9

1540 m/s.

This speed can vary based on the type of tissue.

Question 10

What is the typical amplitude value in soft tissue?

Answer 10

1 - 3 MPa.

MPa stands for megapascal, a unit of pressure.

Question 11

Fill in the blank: The distance or length of one complete cycle of a sound wave is known as _______.

Answer 11

wavelength.

Wavelength is typically measured in millimeters (mm).

Question 12

What is the speed of sound in bone?

Answer 12

3500 m/s.

Bone has a higher speed of sound compared to soft tissue.

Question 13

True or False: Ultrasound is defined as sound waves greater than 20,000 Hz.

Answer 13

True.

Ultrasound is used in medical imaging and other applications.

Question 14

What is the definition of power in sound waves?

Answer 14

The rate of energy transfer or the rate at which work is performed.

Power is measured in watts.

Question 15

What is the typical value for the power of sound in soft tissue?

Answer 15

0.1 - 0.8 W/cm².

This reflects the intensity of ultrasound used in diagnostics.

Question 16

List the parameters that are adjustable in sound wave properties.

Answer 16

• Period
• Frequency
• Amplitude
• Power
• Intensity
• Wavelength
• Speed

Each parameter plays a crucial role in determining the characteristics of sound waves.

Question 17

What is the speed of sound in air?

Answer 17

330 m/s

This is the speed at which sound travels through air.

Question 18

What is the speed of sound in water?

Answer 18

1,480 m/s

This reflects the faster propagation of sound in water compared to air.

Question 19

What is the range of speed of sound in metal?

Answer 19

2,000-7,000 m/s

Sound travels significantly faster in metals due to their dense molecular structure.

Question 20

Define stiffness.

Answer 20

The ability of an object to resist compression.

Stiffness is a measure of how much an object deforms under stress.

Question 21

Define density.

Answer 21

The relative weight of a material.

Density is often expressed as mass per unit volume.

Question 22

How does the speed of sound change in different materials?

Answer 22

Increases in water and metal, decreases in air.

The speed of sound generally increases with the density and stiffness of the medium.