U.s. Physics (Sound Waves)

Front 1

What is SOUND?

Back 1

A mechanical energy transmitted by pressure waves in a material medium.

Front 2

Propagation of sound

Back 2

Sound Waves only exist in media containing molecules or particles, including air, water, and tissues in the body.

Front 3

What is ENERGY?

Back 3

The ability to do WORK.

Front 4

What is the source of sound waves in ultrasound?

Back 4

Piezoelectric Transducer

Front 5

How does sound travel?

Back 5

In the form of a WAVE.

Front 6

What is a WAVE?

Back 6

A coordinated disturbance, moving at a fixed speed, through a medium.

Front 7

FYI: Regarding sound waves

Back 7

They move very fast and generally do not produce visible changes in a medium, so it's difficult to see them.

Front 8

If a wave needs a medium to propagate, it's a ___________ wave.

Back 8

MECHANICAL

Front 9

If a wave does NOT need a medium to propagate, it's an ___________ wave.

Back 9

ELECTROMAGNETIC

Front 10

All waves are an ___________ transfer, most often through cyclical variations.

Back 10

ENERGY

Front 11

The naming of waves as mechanical is due to the physical interaction between the wave and the medium. The interaction produces FOUR possible changes called __________ variables:

Back 11

ACOUSTIC

1) Pressure

2) Density

3) Temperature

4) Particle Motion (distance)

Front 12

Density is defined as:

Back 12

Mass/Volume kg/m^3

Front 13

Sound is a ____________, ___________ wave.

Back 13

LONGITUDINAL, MECHANICAL

Front 14

For a longitudinal wave, the energy is transported by a series of ___________ and ______________ of the medium particles.

Back 14

COMPRESSIONS

RAREFRACTIONS

Front 15

What mechanism transfers energy from one location to another?

Back 15

WAVE

Front 16

When a wave is repetitious, the wave is considered to be ___________.

Back 16

CYCLICAL

Front 17

Ultrasound is primarily ________ ________.

Back 17

CYCLICAL WAVES

Front 18

Sound CANNOT travel through a _____________.

Back 18

VACUUM

(it MUST have a medium)

Front 19

Which direction does sound travel in?

Back 19

A STRAIGHT line

Front 20

Ultrasound waves are _____________.

Back 20

LONGITUDINAL

Front 21

Sound who's frequency is greater than 20 kHz is termed ____________.

Back 21

ULTRASONIC

Front 22

Any sound wave with a frequency between 20 to 20,000 Hz is defined as ....

Back 22

The human audible range

Front 23

1 kilo =

Back 23

1,000 hertz

Front 24

The range of frequencies from 2 MHz to 12 MHz is specified as...

Back 24

The diagnostic range for ultrasound purposes

Front 25

*RANGE OF SOUNDS*

(know this!!!)

Back 25

0 - 20 Hz (below human audible)

20 Hz - 20 kHz (human audible)

> 20 kHz (ABOVE human audible)

2 MHz to 12 MHz (diagnostic U.S)

Front 26

Mechanical waves

Back 26

Requires a physical interaction, it refers to the fact that there is an interaction between the wave and the medium through which the wave propagates.

Front 27

Sound is a ____________ wave.

Back 27

LONGITUDINAL

Front 28

The medium where the molecules are compressed means...

Back 28

They're squeezed together; aka COMPRESSION.

Front 29

The medium where the molecules are stretched apart is called...

Back 29

Rarefied.

Front 30

COMPRESSION

Back 30

Is when the molecules are drawn close together giving a high density, high pressure.

Front 31

RAREFACTION

Back 31

Is when the molecules are drawn apart giving a lower density, lower pressure.

Front 32

PRESSURE

Back 32

Concentration of force, or Force per area.

Front 33

Measurement of PRESSURE

Back 33

Pascal (Pa)

Front 34

In the COMPRESSION phase of the sound wave, the pressure ____________.

Back 34

INCREASES

Front 35

During the RAREFACTION phase of the wave, the pressure....

Back 35

DECREASES.

Front 36

How does pressure vary as the wave propagates through a medium?

Back 36

CYCLICALLY

Front 37

4 ACOUSTIC VARIABLES created by sound.

Back 37

1) Pressure

2) Density

3) Temperature

4) Particle Motion

Front 38

What is used to quantify the strength of a wave?

Back 38

Pressure/ acoustic pressure

Front 39

Pressure Amplitude

Back 39

As the sound wave travels, the pressure distribution continuously changes.

Front 40

Most common unit to measure pressure...

Back 40

PASCAL (Pa)

Front 41

What describes the weight of a material?

Back 41

It's DENSITY

Front 42

As density increases, speed ________.

Back 42

Decreases

Front 43

During compression, density is ___________.

Back 43

Increased

Front 44

During rarefraction, density is _____________.

Back 44

Decreased

Front 45

Sound travels fastest through _________ density mediums.

Back 45

Low

Front 46

The concentration of mass in a volume is?

Back 46

Density

Front 47

How do we measure density?

Back 47

D= mass/Volume

p= kg/cm^2

(the "p" represents the Greek symbol for density, called a "roe")

Front 48

As particles go from a higher to lower concentration, the ____________ will fluctuate cyclically.

Back 48

Temperature

Front 49

Three well known units for Temperature:

Back 49

1) Kelvin

2) celsius

3) fahrenheit

Front 50

What are the 7 ACOUSTIC PARAMETERS?

Back 50

1) Wavelength

2) period

3) frequency

4) amplitude

5) power

6) propagation speed

7) intensity

Front 51

What is the Greek letter used to describe wavelength?

Back 51

The lamda

Front 52

What is described as the distance from one peak compression to another peak compression, or one rarefraction to another rarefraction?

Back 52

A WAVELENGTH

Front 53

The distance or length of one complete cycle.

Back 53

Wavelength

Front 54

Wavelength depends on the characteristics of both _________ and the _____________.

Back 54

The Source and the medium

Front 55

Wavelength equation

Back 55

lamda= c/f

c= propagation velocity

f= frequency