Physics Exam

How much bigger is 1 billion then 1000

1 billion is 1 million times larger than 1000. 1,000,000

A sonographer measures the perimeter of anatomical structure. Which of the following choices is a reasonable value for the measurement

15 mm. Perimeter means the length of the outer boundary of a structure therefore should be measured in millimeters centimeters inches etc.

What is the best estimate for the speed of sound in a tendon

1754 m/s. Sound travels slightly faster in a tendon than in soft tissue

What is the range of frequencies emitted by transducers used in ultrasonic imaging

2 to 15 MHz or 2 to 15 million cycles per second

The maximum value of the density of an a acoustic wave is 60 pounds per square inch while the minimum density is 20 pounds per square inch. What is the amplitude of the wave

20 pounds per square inch. Subtract the minimum from the maximum then divide by 2. (60-20=40 40/2=20 ponds per square inch)

The amplitude of an acoustic wave decreases from 27 pascals to 9 pascals. If the initial power in the wave was 27 watts, what is the wave's final power

3 watts. 27 divided by 9 = 3 watts or 1/9th it's original power

A sack contains 6 pounds of flour. The contents of the bag are increased by a factor of five. How much flour is in the bag

30 pounds. To increase means to multiply

What is the speed of sound in air

330 m/s

The frequency of a continuous acoustic wave is 5 MHz. The wave is then pulsed with a duty factor of 0.1. What is the new frequency

5 MHz or 5 million per second. Frequency is the reciprocal of the period. The wave being pulsed or continuous does not change the frequency

The volume of a cystic structure is estimated from sonographic data. Which of the following is an acceptable measurement of this volume

6 mm³. Cubed. Units of volume are length cubed

How many nano seconds are in 7 seconds

7 billion. Nano means billionth

Compare 2 sound waves A & B. The frequency of wave A is 1/3 that of wave B. How does the period of wave A compare to the period of wave B

A is 3 times as long as B. Frequency and period are reciprocals.

Sound is best described as what

A series of compressions and rarefractions

What is the reciprocal of 1000

.001 - when multiplied together reciprocal numbers have a value of 1

What is the range of periods commonly found in the waves produced by ultrasound systems

.06 to .5 µs. The period is the time of a single cycle. Period is the reciprocal of frequency.

A wave with a frequency of 15 MHz has a period of what

.06 µs

A wave with a frequency of 2 MHz has a period of what

.5 µs

What is the wavelength of 10 MHz sound in soft tissue

0.15 mm wavelength = 1.54 divided by frequency

How can the volume of an irregularly shaped object be measured most accurately

By immersing it in water. The volume of an object can be accurately measured by the water that is displaced

2 sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has a longer spatial pulse length

Cannot be determined. Spatial pulse length is equal to the wavelength multiplied by the number of cycles in the pulse. The number of cycles that comprise each pulse is not provided

2 sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has the lowest power

Cannot be determined. The power is not related to its frequency. No information is given about the power

Select the sequence that appears in increasing order

Centi, Deci, Deca, Hecto

What two properties establish sound's propagation speed in a given medium

Density and stiffness

What are the units of density

Density is measured in pounds or kilograms

Two waves arrive at the same location and interfere. The resultant sound wave is smaller than either of the two original waves. What is this called

Destructive interference

How are scores on the ultrasound board exams related to study time

Directly related

How are caloric intake and weight related

Directly related. Calories increase weight increases

What are the units for wavelength

Distance

What is the reciprocal of period

Frequency and are related in 2 ways. As 1 increases the other decreases and when multiplied together, the result is unity. IE a wave with a period of 1 hundredth of a second has a frequency of 100 per second or 100 Hz

The amplitude of an acoustic wave is increased. Which of the following will most likely remain unchanged

Frequency and period are not related to amplitude, and remain unchanged

What term describes the number of cycles that in acoustic variable completes in a second

Frequency. Frequency can be thought of the number of events in a specific time

Lists media in increasing order of propagation speeds

Gas, liquid solid

What are the units for Pulse repetition frequency or PRF

Hertz

The characteristics of 4 media are described as high density & high elasticity, low density & high stiffness, low stifness & low density, & low compressibility & low stiffness. Which of the media has the slowest propagation speed

High density and high elasticity Speed is determined by density and stiffness. The opposite of stiffness is elasticity. High elasticity = slow speed & high density = slow speed

Is the speed of sound traveling through bone higher or lower than soft tissue

Higher. Speed of sound traveling through bone is 2-3 times faster than in soft tissue Bone is 3-5 km/sec. Soft tissue is 1.54 mm per micro sec

The speed of red blood cells traveling through a blood vessel is 750 cm/s. You are asked to measure the speed in miles per hour. What information would be sufficient for you to complete your task

How many seconds per hour and the number of miles in a centimeter. we require two pieces of information. Relationship between seconds in hours and the relationship between miles and centimeters.

What is the characteristic of acoustic waves with frequencies exceeding 20,000 Hz when compared with waves having frequencies of less than 20,000 Hz

Humans can not hear them. Waves with frequencies exceeding 20 kHz are ultrasonic and inaudible to humans. They travel at the same speed and attenuate faster than waves with lower frequencies

A particle with an a transverse wave is traveling vertically. What is the direction of the waves propagation

If a transverse wave is traveling and vertically, the particles in the waves are traveling horizontally

The intensity of an ultrasound beam is defined as what

Intensity is the power of the beam divided by the area of the beam.

What are the units of intensity

Intensity is watts per cm squared. Power has units of watts. Beam area has units of square cm

When the power in an acoustic beam is doubled and the cross-sectional area of the beam is halved, then what happens to the intensity of the beam

Intensity will be 4 times larger. Intensity is equal to power divided by beam area

Which term best describes the relationship between frequency and wavelength for sound in soft tissue

Inversely related. Higher frequency have shorter wavelengths Lower frequencies have longer wavelengths

Mathematically, when a number is squared, the number is multiplied by what

Itself. IE 5 squared is 5 times 5

Which of the following types of waves do not require a medium in order to propagate

Light, Heat, television. These are capable of traveling through a vacuum

2 sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. What sound waves have a longer period

Lower frequencies have longer periods

2 sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has a longer wavelength

Lower frequencies have the longer wavelength

If Sound travels at exactly 1540 m/sec in a particular medium, then the medium

May be soft tissue. Sound travels through soft tissue at 1540 m/sec however, other media have the same propagation speed

Which of the following describes the characteristics of a sound wave

Mechanical and longitudinal

Match the following prefixes and their meanings

Mega millions. Hecto hundreds. Milli thousandths th. Kilo thousands. Nano billionths th. Giga billions

Which term is the reciprocal of mega

Micro. Mega means million. The reciprocal of million is millionth or micro

What are the units associated with the circumference of a circle

Millimeters. The circumference of the circle is the length of the outer boundary and is measured in units of length

2 sound waves with frequencies o 5 MHz & 3 MHz travel to a depth of 8 cm in a medium & then reflect back to the surface. Which acoustic wave arrives first at the surface of the body

Neither. All sound waves regardless of frequency travel at the same speed in a specific medium

Can the sonographer alter the period of an ultra sound wave that is produced by a basic transducer

No The sonographer cannot adjust the period Or frequency of the wave produced by a basic transducer

Can the sonographer adjust the duration of an acoustic pulse and does it depends upon the maximum imaging depth

No the sonographer cannot change the pulse duration. It is a constant value, and is not dependent on imaging depth

Can the sonographer adjust the duration of an acoustic pulse and does it depends upon the pulses propagation speed

No the sonographer cannot change the pulse duration. It is a fixed picture of the transducer and alter sound system. It does not depend on the propagation speed

With standard ultrasound pulses, does the frequency of the ultrasound change significantly as the wave propagates through the body

No, the frequency remains constant

Do lower frequency sound create higher quality images with greater detail

No. Higher frequency usually produces higher quality images with greater detail

Is the wavelength of an acoustic wave shorter when it is pulsed rather than continuous

No. Wavelength is the length of 1 complete cycle. Wavelength does not change whether or not the wave is pulsed or continuous.

What are the units of particle motion

Particle motion is measured in units of distance such as miles or centimeters

What can be considered a unit of frequency

Per day, cycles per second, Hix, hertz. . However cycles is incomplete. Cycles informs us of a number of events, but does not inform us of the duration of time in which those events occur

The pulse duration is expressed in the same units as the

Period. The pulse duration and period are measured in time.

What are the acoustic variables that identify sound waves

Pressure, particle motion, density,

Propagation speed can be correctly recorded with which units

Propagation speed is recorded as a distance per unit of time, such as miles per hour, mm/sec, km/sec, feet/sec, or inches per year

When the sonographer increases the maximum imaging depth during the exam, what happens to the frequency

Remains unchanged. Imaging depth and frequency are unrelated

A longitudinal wave propagates from east to west at a speed of 2 mph. What is the direction of motion of the particles within the wave

Since the wave is traveling from east to west, the particles in this wave will move alternately from east to west and then from west to east. A longitudinal wave is defined as a wave whose particles vibrate back and forth in the same direction that the wave is propagating

Compared to soft tissue, the speed of an acoustic wave through lung is

Slower. The speed of sound in lung is 0.5 to 1.0 km/sec. Soft tissue is 1.54 mm per micro sec

What is the propagation speed of a 5 MHz sound wave in soft tissue

Sound propagates through soft tissue at 1.54 mm per micro sec regardless of frequency

What type of waves cannot travel through a vacuum and require a medium in order to propagate

Sound waves

Compressibility describes a characteristic of a medium. Which 2 terms describe the same property as compressibility.

Stiffness & elasticity. Compressibility describes its ability to reduce its volume when force is applied to it. Elasticity has the same meaning as compressibility however, stiffness is the opposite of compressibility

What happens when the power in an ultrasound beam is unchanged, and at the same time, the beam are doubles

The beams intensity is halved. Intensity=power divided by beams area.

Waves that exist at the same location and time will combine. What is this called

The combination of many waves into a single wave is called interference

What is the name of the horizontal axis of a graph

The horizontal axis of a graph is the X axis and extends side to side

What happens to the intensity of an ultrasound beam when the beam's cross-sectional area remains unchanged while the amplitude of the wave triples

The intensity increases ninefold. Intensity equals amplitude squared

What happens to an acoustic beam's intensity when the power in the beam increases by 25% while the cross-sectional area of the beam remains the same

The intensity is also increase by 25%. The intensity is equal to the power divided by the beams area. If the power increases by 25% while the beam's area is unchanged, then the intensity is also increases by 25%

If the power of the beam is tripled while the cross-sectional area of the beam remains the same, what happens to the intensity

The intensity is tripled as well. Power is the same as intensity

The speed at which a wave travels through a medium is determined by what

The medium's properties only. All sound waves of any frequency, period, intensity, and power travel at the same speed in a particular medium

With standard ultrasonic imaging, what happens to the period of a wave as it propagates

The period and frequency of the wave remains the same

A force is applied to a surface. If the force is tripled in the surface area over which the force is applied is also tripled, what is the new pressure

The pressure remains unchanged. Pressure is defined as the amount of force divided by the area to which it is applied. If the applied force is triple, and at the same time, the area over which it is a plied is tripled the pressure remains unchanged

What determines the period of an ultrasound wave

The sound source or transducer. The waves period Is unrelated to the medium through which the sound travels. It will not change as the wave moves from one medium to another

What is the vertical axis of a graph called

The vertical axis of a graph is called the Y axis and extends up and down

The wavelength of an acoustic wave is determined by what

The wavelength is determined by both the sound source, transducer, and the medium through which it travels through.

Which of the following is true of all waves

They all carry energy from one site to another

How is weight related to a sonographers time spent exercising

They are inversely related. Exercise time increases weight decreases

All of the following are true about sound waves

They are mechanical, they carry energy from place to place, they generally travel in a straight line

What is the characteristic of acoustic waves with frequencies of less than 20 Hz when compared with waves having frequencies of more than 20 Hz

They travel at the same speed and attenuate at a lesser rate than that of higher frequencies, and are inaudible to humans

The direction of motion of a particle and a wave is perpendicular to the direction of the propagation of the wave. What type of wave is this

Transverse.

2 waves, a 5 MHz ultrasonic wave and a 5 kHz audible wave, travel through soft tissue. True or false. Both the 5 MHz and 5 kHz waves travel at similar speeds through the medium

True. All sound waves travel at the exact same speed through a particular medium

If the periods of 2 waves are the same, are the frequencies of the waves also be the same

True. Frequency and periods are reciprocals. When periods of 2 waves are identical, the frequencies must also be identical

2 waves, a 5 MHz ultrasonic wave and a 5 kHz audible wave, travel through soft tissue. True or false. The period of the 5 MHz ultrasonic wave is less than the period of the audible wave

True. The period & frequency of any wave are inversely proportional. The 5 MHz is a higher frequency and will have a shorter period

Is the period of an ultrasound wave related to the frequency and is the same, regardless of whether the wave is pulse or continuous

True. The period of a wave is a characteristic of each individual cycle in the wave, regardless if the wave is pulsed or continuous.

3 sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5 mW, & 15 mW. They all travel through 3 media-wood, brick, and fat with identical thicknesses of 5 cm. True or false. The waves travel through all 3 media at different speeds because the media are different

True. The waves travel at different speeds because of the different densities and stiffnesses of media in which they are traveling in

An ultrasound pulse propagates from soft tissue through a mass. Sound's propagation speed in the mass is 1575 m/s. True or False. The wavelength increases while the wave travels through the mass

True. Wavelength is dependent on both the sound source and the medium. The speed of sound in soft tissue is 1540 m/sec, and through the mass is 1575 m/sec. As a wave travels in a faster medium, its wavelength increases

Ultrasound is defined as a sound with a frequency of what

Ultrasound is an acoustic wave so high humans can not hear it, with a frequency of at least 20,000 Hz, 20 kHz or 0.02 MHz

What is the units for pressure

Units of pressure include pascals (Pa) and pounds per square inch (lb/in2)

What are the units of pulse duration

Units of time typically 0.3 to 2 microseconds, but can be repored in any units of time

The propagation speeds of ultrasound waves in muscle, liver, kidney, and blood are

Very similar to each other

What are the units of volume

Volume has units of length cubed such as inches cubed or cubic meters

The power of an ultrasound wave can be reported with which units?

Watts. Think light bulb power = watts

The wavelength of a cycle in an ultrasound wave can be reported with what units

Wavelength is reported in units of distance. In soft tissue, the wavelength typically ranges from 0.15 mm to 0.75 mm

Do shorter wavelength sound create higher quality images with greater detail

Yes. Shorter wavelength = higher frequency sound = higher quality images with greater detail

Does soft tissue have an imaginary construct that actually does not exist

Yes. Soft tissue is an imaginary structure with characteristics that represent an average of body tissues, includin muscle, blood, kidney & spleen. It is used as an approximation

Do waves in ultrasound range behave in the same general manner as sound waves that are audible

Yes. The primary difference is that one is audible by humans and one is not

Does the pulse duration of an ultrasound and transducer system change significantly while the components remain unchanged

Yes. The pulse duration is the timespan that a pulse exists. It is determined by the ultrasound system and the transducer.

Can a sonographer routinely change the power of a a wave emitted by the transducer used id ultrasound imaging

Yes. The sonographer can adjust the power and amplitude on the machine. Power and amplitude are directly related so when one goes up, the other goes up

With standard diagnostic imaging instrumentation, does the sonographer have the ability to vary the amplitude of the sound wave produced by the transducer

Yes. The sonographer can adjust the strength of the ultrasound signal that the transducer creates by increasing the power output, thus creating a more violent vibration of the piezoelectric crystal creating a stronger wave

If sound does not travel at 1540 m/sec in a medium, than the medium

cannot be soft tissue. Sound through soft tissue travels at exactly 1540 m/sec

As an ultrasound wave travels through the body, what usually happens to its amplitude

decreases or attenuates

As sound travels in the body, what typically happens to the intensity of the wave

decreases or attenuates. Amplitude, power and intensity are 3 ways to measure the strength of the beam, and all 3 decrease as sound propagates

Typically, as an ultrasound wave travels through soft tissue, the power of the wave does what

decreases or attenuates. Both power and amplitude measure strength and both decrease as they travel

What are the units for density

mass per volume

2 sound pulses travel through the same medium. One waves frequency is 2 MHz and the other is 10 MHz. Which pulse has a lower propagation speed

neither pulse. The propagation speeds of all sound waves are identical while traveling in a specific medium

What is the best estimate of the distance that sound can travel in soft tissue in 1 second

sound travels 1540 meters per second in soft tissue or approximately 1 mile per second

What determines the pulse duration

the source of the wave, transducer or ultrasound system. The pulse duration does not include listening time

What established the frequency of an ultrasound wave

the transducer AKA sound source

What determines the initial amplitude of an ultrasound wave

the transducer or sound source by the vibration of the piezoelectric crystal in the transducer. The greater the vibration of the crystal, the larger amplitude of the wave

What are the acceptable units for the amplitude of an acoustic wave

the units of amplitude are typically cm for particle motion and pascals for pressure.The acoustic variables are pressure, density, & particle motion

As sound travels through a medium, what term describes the effects of the medium on the soundwave

Acoustic propagation properties

Which of the following units are appropriate to describe a period of ant acoustic wave

Any units of time such as minutes, seconds or microseconds

Which of the following is a measure of area

Area is measured in units of distance squared

What are the units of a pressure measurement of an acoustic wave

Atmospheres, pascals, millimeters of mercury, and pounds per square inch. However pressure is most often reported and units of pascals

What is the wavelength of a 2 MHz sound in soft tissue

1.54 divided by 2 = 0.77 MHz wavelength = 1.54 divided by frequency

The propagation speed of continuous wave ultrasound is 1.8 kilometers per second. The wave is then pulsed with a duty factor of 50%. What is tge new propagation speed

1.8 km/sec The speed of sound in a medium is determined only by the medium. There is no difference whether or not the wave is pulsed or continuous.

The final amplitude of an acoustic wave is reduced to 1/2 of its original value. The final power is how much the original power

1/4 the original power. Changes in power are proportional to changes in amplitude squared, therefore 1/2 times 1/2 = 1/4

What is the reciprocal of 5

1/5

What is the reciprocal of 1/10

10

A bouquet has 30 flowers. The size of the bouquet is decreased by a factor of 3. How many flowers or remain

10. To decrease means to divide

What term is used to describe the effects of an alter sound wave on living tissues

Biological effects or bioeffects

When the elasticity of a medium is high, what else is high

Compressibility. High elasticity is the same as high compressibility

A pair of waves are in phase. What occurs when these waves interfere

Constructive interference. The single wave that results from the combination of the two in phase waves will always have a higher amplitude than either of the original waves

Which of the following is used to measure volume

Cubic meters

How can sound characterized

Cyclical oscillations in certain variables. A wave is a rhythmical variation throughout time

2 waves, a 5 MHz ultrasonic wave and a 5 kHz audible wave, travel through soft tissue. True or false. The ultrasound wave travels much faster than the audible wave.

False. All waves travel at the same speed, regardless of there frequencies. In soft tissue sound propagates at a speed of 1.54 mm or 1540 m/sec

An ultrasound pulse propagates from soft tissue through a mass. Sound's propagation speed in the mass is 1575 m/s. True or False. The power in the wave increases as it travels through the mass

False. Power of a beam diminishes as it travels as a result of attenuation.

An ultrasound pulse propagates from soft tissue through a mass. Sound's propagation speed in the mass is 1575 m/s. True or False. The period of the sound wave decreases as it travels through the mass

False. The period of the wave is determined by the sound source only

An ultrasound pulse propagates from soft tissue through a mass. Sound's propagation speed in the mass is 1575 m/s. True or False. The frequency of the wave increases as it travels through the mass

False. The wave's frequency is determined by the transducer or the sound source only, and is unaffected by the tissue through which it travels

3 sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5 mW, & 15 mW. They all travel through 3 media-wood, brick, and fat with identical thicknesses of 5 cm. True or false. The sound waves travel through all 3 media at different speeds because the waves have different powers

False. The waves travel at different speeds because of the different densities and stiffnesses of media in which they are traveling in

3 sound waves with identical frequencies of 3 MHz have powers of 2 mW, 5 mW, & 15 mW. They all travel through 3 media-wood, brick, and fat with identical thicknesses of 5 cm. True or false. The waves travel through all 3 media at the same speed since they have identical thicknesses

False. The waves travel through 3 different types of media with vastly different densities and stiffnesses. Having similar frequencies is irrelent

2 waves, a 5 MHz ultrasonic wave and a 5 kHz audible wave, travel through soft tissue. True or false. The wavelength of the 5 MHz wave is greater than the wavelength of the 5 kHz wave

False. When 2 sound waves travel through the same medium, the higher frequency wave has the shorter wavelength. 5 MHz has a higher frequency and therefore a shorter wavelength

Infrasound is defined as a sound with a frequency of what

Infrasound is an acoustic wave so low that humans can not hear it, with a frequency of less than 20 Hz

A sonographer adjusts the output power of the wave emitted by the transducer. Which of the following also changes

Intensity