Chapter 2 - Sound Flashcards by Katie Amason

The effects of the sound wave upon the biological tissue is called____?
❤️

Biologic effects

❤️

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Sound is a type of wave that carries ____ , from place to place.
❤️

ENERGY ❤️

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Sound is series of ____ and ____

❤️

Compressions and rarefactions

❤️

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Areas of increased pressure and density are called ____?

Compressions

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areas of decreased pressure and density are called ____?

Rarefactions

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Sound must travel through a _____

Medium

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Sound cannot travel through a _____

Vacuum

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What type of waves is sound made of???

Mechanical and longitudinal

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Sound travels in a _____ line

Straight

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_____ ______ IDENTIFY which waves are sound waves

Acoustic variables

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When an _____ _____ changes rhythmically in time, a _____ _____ is present.

Acoustic variable

sound wave

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What are the 3 acoustic variables?

Pressure ❤️

Density

Distance

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____ is this concentration of force within an area,

Force/area❤️

Pressure

Units: pascals (Pa) ❤️

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____ is the concentration of mass within a volume

Density

Units: kg/cm^3

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_____ measure of particle motion

Distance

Units: cm,feet & miles

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What are the two types of waves?

Transverse and longitudinal

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_____ ______ : particles move in a perpendicular direction to the direction of the wave

Transverse waves

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_____ _____ : particles move in the same direction as the wave

Longitudinal

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Regions of higher density and pressure are called ______

Compressions

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Regions of lower density and pressure are called _____

Rarefactions

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Acoustic _____ inform us of which waves are sound

Variables

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Acoustic _____ describe the features of a particular sound wave

Parameters

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Name the seven acoustic parameters

Period 
Frequency 
Amplitude 
Power
Intensity 
Wavelength 
Speed

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The time required to complete a SINGLE cycle is called a _____

Or aka as the time from start of a cycle to the start of the next cycle

Period

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The typical values for a Period is _____

0.06 to 0.5 ùsecond (less than 1-millionth of a second)

A period is determined by _____

Sound source

Number of CERTAIN EVENTS that occur in a particular time

Frequency

What are the units for frequency?

Per second , 1/sec, Hertz, Hz Hertz is Just another way of saying per second

What are the typical values for frequency???

2 MHz to 15MHz

Frequency affects ___ and _____

Penetration and axial resolution (image quality)

A wave exceeding 20,000Hz (20 kHz)

Ultrasound

____ this frequency is so HIGH that it cannot be heard by man

Ultrasound

Frequencies between 20Hz and 20,000Hz

Audible sound Heard by man

Sound with frequencies less than 20Hz

Infrasound

This sound wave cannot be heard by man because it is so LOW

Infrasound Less than 20Hz

_____ and ____ are related to each other, they are RECIPRICOALS

Frequency and period

The complimentary unit for sec is _____

The rate that which work is performed or the rate of energy transfer

Power

What is the unit for power?

Watts

Power _____ as sound propagates through the body

Decreases

Power is ______ to the waves amplitude squared

Proportional

If amplitude is doubled, the power is increased by a factor of _____?

Four (quadrupled) 2x2=4

The concentration of energy in a sound BEAM

Intensity

The beams power divided by the beams cross sectional area is called

Intensity

Equation for intensity

Watts/cm^2 Power(watts)/ beam area (cm^2)

Intensity ____ as sound propagates through the body

Decreases

What type of relationship does intensity and POWER have?

Direct Proportional When one goes up the other goes up

What type of relationship does intensity and AMPLITUDE have?

Proportional | Direct

Intensity is proportional to the amplitude of the wave ____

SQUARED

Intensity is proportional to the _____ of the wave squared

Amplitude

The effects of the medium upon the sound wave is called ____ ? ❤️

Acoustic propagation properties | ❤️

If the AMPLITUDE is doubled, the intensity is increased by a factor of _____

Four 2x2=4

If amplitude is quartered, the intensity is reduced by a factor of _____

16 (1/4)^2 = 1/4 x 1/4 = 1/16

What is the definition of wavelength?

The length or distance of a single cycle.

What are the units used for wavelength?

Meters Mm Or any unit of LENGTH

Wavelength is the _____ or _____ of a single cycle.

Length or distance

Wavelength is determined by ______?

BOTH the source and the medium

Can wavelength be changed by the sonographer?

What is the equation for wavelength?

Wavelength (mm) = propagation speed (mm/ùs) / frequency (MHz) Or L = C/F

HIGHER frequency waves have _____ wavelengths.

Shorter

LOWER frequency waves have _____ longer wavelength.

Longer

In what type of tissue does sound have a frequency of 1MHz, with a wavelength of 1.54mm?

Soft tissue

In soft tissue, sound has a frequency of ____ has a wavelength of _____ ?

1 MHz and 1.54mm

In soft tissue you divide 1.54mm by ____ in MHz

Frequency

The rate that sound travels through a medium

Propagation speed

What's another name for propagation speed?

Velocity or speed

Units used for propagation speed?

Meters per second | Mm/ùs

Propagation is determined by what?

Medium only - density and stiffness All sound travels through the same speed through any specific medium. Ex. Frequencies of 5mhz and 3mhz travel at the same speed through the same medium.

What is the average speed of all sound ( regardless of frequency) in biological or soft tissue?

1,540 m/s 1. 540 km/s 1. 54 mm/ùs

Lung (air) is less than _____ and ____

Fat, soft tissue and bone

Sound in a _____ medium has a short wavelength

Slow

Sound in a _____ medium has a long wavelength

Fast

The tissue type of air has a speed (m/s) of?

330 m/s

The tissue type of lung has a speed of

300-1,200 m/s

The tissue type of fat has a speed of

1,450m/s

The tissue type for soft tissue and blood has a speed of

1,540

The tissue type for tendon has a speed of

About 1,850 m/s

The tissue type of bone has a speed of

2,000-4,000 m/s

Stiffness and speed move in the ______ direction.

Same

Density and speed move in ______ directions.

Opposite

Bulk modules is the same as _____

Stiffness

Stiffness is related to change in _______

Shape "squishability"

Density is related to ______

Weight

When two waves overlap at the same location and at the same time, they combine into a single new wave.

Interference

Occurs when the amplitude of the new, combined wave is greater than the original two waves.

Constructive interference

What type of phase interferes constructively?

In-phase waves

The amplitude of the new wave is less than one of the original waves.

Destructive interference

What type of phase interfere destructively?

Out-of-phase waves

Chapter 2 - Sound Flashcards

(88 cards)