1.
Sound waves are
Correct Answer
D. Longitudinal mechanical
Explanation
Sound waves are longitudinal mechanical waves. Longitudinal waves are characterized by the particles of the medium vibrating parallel to the direction of wave propagation. In the case of sound waves, the particles of the medium (such as air molecules) vibrate back and forth in the same direction as the wave travels. This vibration of particles creates areas of compression and rarefaction, which result in the propagation of sound energy through the medium. Therefore, sound waves are longitudinal in nature and require a medium (such as air, water, or solids) to propagate.
2.
The frequency closest to the lower limit of US is
Correct Answer
D. 15.000 Hz
Explanation
The frequency closest to the lower limit of the US is 15.000 Hz. This is because the question asks for the frequency closest to the lower limit, and out of the given options, 15.000 Hz is the lowest frequency.
3.
Which is not an acoustic variable?
Correct Answer
D. Intensity
Explanation
4 Variables include: Pressure, Density, Particle Motion (Distance), Temperature
4.
The effects of soft tissue on US are called:
Correct Answer
C. Acoustic propagation properties
Explanation
The effects of soft tissue on ultrasound are referred to as acoustic propagation properties. This term encompasses the way in which sound waves travel through and interact with soft tissues in the body. It includes factors such as absorption, scattering, and reflection of the ultrasound waves as they pass through different types of soft tissue. Understanding the acoustic propagation properties is crucial in interpreting ultrasound images and diagnosing various medical conditions.
5.
All of the following are true EXCEPT:
Correct Answer
A. Two waves with identical frequencies must interfere constructively
Explanation
This statement is not true because two waves with identical frequencies can interfere destructively if they have a phase difference of half a wavelength.
6.
Put in decreasing order
Correct Answer(s)
A. Deca
B. Deci
C. Micro
D. Centi
Explanation
deca -- deci -- centi -- micro
7.
______ is the time to complete on cycle
Correct Answer
C. Period
Explanation
Period is the length of time it takes for one single cycle to occur. Unit of time microsecond (us)
8.
Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
Correct Answer
A. 30 KHz
Explanation
Ultrasonic sound waves are sound waves with frequencies higher than the upper limit of human hearing, which is typically around 20 kHz. The sound waves with frequencies of 30 KHz and 3.00 kHz fall into the ultrasonic range, but 30 KHz is the least useful in diagnostic imaging because it has a higher frequency and shorter wavelength, which makes it more prone to attenuation and scattering in tissues, resulting in poor image quality. In contrast, 3.00 kHz has a lower frequency and longer wavelength, allowing it to penetrate deeper into tissues and produce clearer diagnostic images. The other options, 8 MHz and 8.00 Hz, are not ultrasonic frequencies and are not commonly used in diagnostic imaging.
9.
What is the frequency of a wave with 1 msec period?
Correct Answer
C. 1 kHz
Explanation
The frequency of a wave is the number of complete cycles it completes in one second. In this case, the wave has a period of 1 millisecond, which means it completes one cycle every 1 millisecond. To convert this to frequency, we can use the formula: frequency = 1 / period. So, the frequency of the wave is 1 / 0.001 = 1000 Hz, which is equivalent to 1 kHz.
10.
_____ is the distance covered by one cycle.
Correct Answer
B. Wavelength
Explanation
wavelength is the length of space that one wave occupies, usually measured in mm, meters, inches.
11.
Which of the following is determined by the source and the medium?
Correct Answer
D. Range resolution
Explanation
Range resolution is determined by the source and the medium. Range resolution refers to the ability to distinguish between two closely spaced objects in the range direction. It is influenced by factors such as the wavelength of the signal emitted by the source and the characteristics of the medium through which the signal propagates. A shorter wavelength and a higher propagation speed can improve range resolution, allowing for better discrimination between objects. Therefore, range resolution is dependent on the source and the medium used in the measurement.
12.
Propagation speed = _______ x wavelength
Correct Answer
D. Frequency
Explanation
Propagation speed is determined by the frequency of the wave. The frequency of a wave refers to the number of cycles it completes in a given time period. As the frequency increases, the wavelength decreases, resulting in a higher propagation speed. Therefore, the correct answer is frequency.
13.
As a result of _____ the propagation speed increases.
Correct Answer
C. Decreasing compressibility and decreasing density
Explanation
Increasing stiffness and increasing density would actually decrease the propagation speed, as the wave would have a harder time propagating through a stiffer and denser medium. On the other hand, decreasing compressibility and decreasing density would make the medium less resistant to deformation and less dense, allowing the wave to propagate more easily and at a higher speed.
14.
Sound waves carry energy
Correct Answer
A. True
Explanation
Sound waves carry energy because they are mechanical waves that propagate through a medium by transferring energy from one particle to another. As sound waves travel, they cause the particles in the medium to vibrate, and this vibration transfers energy in the form of kinetic energy from particle to particle. This energy can then be detected and perceived as sound by our ears. Therefore, it is true that sound waves carry energy.
15.
Sound waves are longitudinal waves sound travels in a straight line
Correct Answer
A. True
Explanation
Sound waves are indeed longitudinal waves, meaning that the particles in the medium vibrate parallel to the direction of wave propagation. This is in contrast to transverse waves, where the particles vibrate perpendicular to the direction of wave propagation. Additionally, sound waves do travel in a straight line, as long as the medium through which they are propagating is uniform and undisturbed. However, sound waves can also be affected by factors such as reflection, refraction, and diffraction, which can cause them to deviate from a straight path.
16.
What are the acousitic variables?
Correct Answer
A. Pressure, density, distance
Explanation
The acoustic variables are the properties that describe sound waves. Pressure refers to the force exerted by the sound wave on a surface, density is the mass of the air molecules in the sound wave, and distance is the physical separation between two points in the wave. These variables help us understand and measure the characteristics of sound waves.
17.
What are the acoustic parameters?
Correct Answer
B. Period frequency amplitude power intensity wavelength propagation speed
Explanation
The given answer lists the various acoustic parameters, which include period, frequency, amplitude, power, intensity, wavelength, and propagation speed. These parameters are used to describe and measure different aspects of sound waves. The period refers to the time it takes for one complete cycle of a wave, frequency is the number of cycles per second, amplitude is the maximum displacement of the wave from its equilibrium position, power is the rate at which energy is transferred by the wave, intensity is the amount of energy per unit of area, wavelength is the distance between two consecutive points in a wave, and propagation speed is the speed at which the wave travels through a medium.
18.
A pair of waves are considered out of phase when their peaks occur at the same time and location
Correct Answer
B. False
Explanation
the correct answer to this will be in phase NOT out of phase
19.
Period and frequency are determined by?
Correct Answer
A. Sound source
Explanation
The period and frequency of a sound wave are determined by the characteristics of the sound source. The period refers to the time it takes for one complete cycle of the wave, while the frequency is the number of cycles per second. These properties are influenced by factors such as the vibrating object or instrument creating the sound. The medium through which the sound travels does not directly affect the period and frequency of the sound wave.
20.
Period and frequency are
Correct Answer(s)
A. Inversely
D. Reciprocal
Explanation
Period and frequency are inversely related. This means that as the period increases, the frequency decreases, and vice versa. The reciprocal relationship between period and frequency can be mathematically expressed as: frequency = 1 / period. Therefore, if the period doubles, the frequency is halved, and if the period is halved, the frequency doubles.
21.
Amplitude , power, intensity are determined by the
Correct Answer
B. Sound source
Explanation
The amplitude, power, and intensity of a sound wave are determined by the sound source. The sound source is responsible for creating the vibrations that generate the sound wave. The amplitude of a sound wave is the maximum displacement of the particles in the medium caused by the sound source. The power of the sound wave is the rate at which energy is transferred by the sound source. The intensity of the sound wave is the power per unit area and is also determined by the sound source. Therefore, the correct answer is the sound source.
22.
Amplitude, power, intensity are not adjustable
Correct Answer
B. False
Explanation
all three ARE adjustable
23.
Wavelength is determined by
Correct Answer
C. Both
Explanation
The wavelength of a sound wave is determined by both the sound source and the medium through which it travels. The sound source, such as a musical instrument or a person's voice, produces the sound wave with a specific frequency. The medium, which can be air, water, or any other substance, affects the speed at which the sound wave travels. The wavelength is the distance between two consecutive points of the wave that are in phase with each other. Therefore, both the characteristics of the sound source and the properties of the medium play a role in determining the wavelength of a sound wave.
24.
As frequency increases, wavelength decreases
Correct Answer
A. True
Explanation
As frequency increases, the number of waves passing a given point per second increases. Since the speed of waves remains constant, an increase in frequency means that the waves have less time to travel a certain distance. Therefore, the wavelength, which is the distance between two consecutive points in a wave, decreases. This relationship between frequency and wavelength is known as the inverse relationship, where an increase in frequency corresponds to a decrease in wavelength.
25.
Which type of wavelength sound produces higher quality images with greater detail?
Correct Answer
A. Short
Explanation
Short wavelength sound produces higher quality images with greater detail because shorter wavelengths have a higher frequency and can capture more detailed information. This allows for a more precise representation of the sound waves, resulting in a clearer and more detailed image. Longer wavelength sound, on the other hand, has a lower frequency and captures less detailed information, leading to lower quality images with less detail. Therefore, short wavelength sound is preferred for producing higher quality images.
26.
Propagation speed is determined by
Correct Answer
B. Medium
Explanation
The correct answer is "medium". The propagation speed of sound is determined by the medium through which it travels. Different mediums have different densities and elastic properties, which affect the speed at which sound waves can travel through them. In general, sound travels faster in denser mediums, such as solids, and slower in less dense mediums, such as gases. Therefore, the medium plays a crucial role in determining the propagation speed of sound.
27.
What is the speed in liver?
Correct Answer
C. 1560 m/s
28.
If the power of a wave is tripled the intensity is reduced to one third
Correct Answer
B. False
Explanation
remember , power is related to the intensity (pg.31)
so if power is tripled the intensity is tripled as well
29.
The effects of sound waves on tissue in the body are called?
Correct Answer
B. Bioeffects
Explanation
The term "bioeffects" refers to the effects of sound waves on tissue in the body. Sound waves can have various impacts on biological systems, including heating, cavitation, and mechanical stress. These effects can be both beneficial, such as in therapeutic ultrasound, or harmful, such as in excessive exposure to loud noise. Understanding the bioeffects of sound waves is crucial in fields like medicine and occupational health to ensure the safe and effective use of sound-based technologies.
30.
The start of a pulse to the end of that pulse is reffering to ....
Correct Answer
D. Dulse duration
Explanation
The term "pulse duration" refers to the time it takes for a single pulse to occur, from the beginning to the end. It is a measure of the length of time that the pulse is active or "on". Therefore, the correct answer is "pulse duration".
31.
What is pulse duration's formula?
Correct Answer
D. # of cycles / frequency
Explanation
The pulse duration of a wave is defined as the time it takes for one complete cycle of the wave. It is measured in seconds. In this case, the formula for pulse duration is given as the number of cycles divided by the frequency. This makes sense because dividing the number of cycles by the frequency gives the time it takes for one complete cycle. Therefore, the correct answer is "# of cycles / frequency".
32.
Pulse duration is directly related to the frequency
Correct Answer
B. False
Explanation
pulse duration is INVERSELY proportional to the frequency
recall that pulse duration formula is # cycles / frequency
pg. 48
33.
What is spatial pulse length definition?
Correct Answer
A. Distance that a pulse occupies in space from start to the end of a pulse
Explanation
The spatial pulse length definition refers to the distance that a pulse occupies in space from start to the end of a pulse. This means that it measures the physical length of the pulse as it travels through space. It does not refer to the time it takes for the pulse to travel or the number of pulses transmitted per second.
34.
Is pulse repition period (PRP) adjustable?
Correct Answer
A. Yes
Explanation
The pulse repetition period (PRP) is the time interval between consecutive pulses in a pulse train. It determines the maximum range that can be measured by a radar system. The PRP is adjustable in radar systems to accommodate different operating conditions and requirements. By adjusting the PRP, the radar system can optimize its performance for various purposes such as increasing range resolution or reducing the effects of clutter. Therefore, the statement "yes" is correct because the PRP is indeed adjustable in radar systems.
35.
Depth of view describes the minimum distance into the body that an ultrasound system is imaging
Correct Answer
B. False
Explanation
describes the MAXIMUM distance
36.
How are PRP and depth related?
Correct Answer
A. Directly
Explanation
when PRP increases , depth of view increases
37.
With deeper imaging will the listening time lengthen?
Correct Answer
A. Yes
Explanation
The correct answer is "yes" because deeper imaging allows for a more detailed examination of the subject, which in turn can lead to a longer listening time. This is because the additional information obtained from deeper imaging can provide more insights and nuances that may require more time to fully comprehend and analyze.
38.
PRF and frequency are related
Correct Answer
B. False
Explanation
The statement "PRF and frequency are related" is false. PRF stands for Pulse Repetition Frequency, which is the number of pulses emitted per second. Frequency, on the other hand, refers to the number of cycles of a wave that occur in one second. While both PRF and frequency are related to the timing of waveforms, they are not directly related to each other. PRF is more commonly used in radar systems, while frequency is a fundamental property of any wave.
39.
When the sonographer adjusts the depth of view to 30 cm, what happens to the pulse repetition frequency?
Correct Answer
A. Reduced
Explanation
When the sonographer adjusts the depth of view to 30 cm, the pulse repetition frequency is reduced. This is because the depth of view refers to the distance that the ultrasound waves need to travel. When the depth of view is increased, the ultrasound waves need to travel a longer distance, and therefore, the pulse repetition frequency needs to be reduced in order to maintain image quality.
40.
Which of these values for PRF would have the longest PRP?
Correct Answer
C. 1 Hz
Explanation
the correct answer is C because the question asks for the longest PRP
since PRF and PRP are reciprocals you will have to look for the lowest PRF
41.
What is the duty factors formula?
Correct Answer
D. Pulse duration / PRP x100
Explanation
The duty factor is a measure of the amount of time a pulse is "on" or active compared to the total pulse repetition period (PRP). It is calculated by dividing the pulse duration by the PRP and then multiplying by 100 to express it as a percentage. Therefore, the formula for calculating the duty factor is pulse duration / PRP x 100.
42.
What occurs on shallow imaging on PRP?
Correct Answer
A. Shorter PRP
Explanation
Shallow imaging on PRP refers to the use of a shorter pulse repetition period (PRP) in ultrasound imaging. PRP is the time interval between consecutive ultrasound pulses. When the PRP is shorter, it means that the ultrasound machine is sending pulses more frequently. This results in a higher pulse repetition frequency (PRF) which allows for better resolution and imaging of superficial structures. Therefore, a shorter PRP would lead to improved visualization of shallow tissues and structures during ultrasound imaging.
43.
The sonographer changes duty factor when imaging depth is altered
Correct Answer
A. True
Explanation
The duty factor is the fraction of time that the ultrasound system is transmitting a pulse. When imaging depth is altered, the sonographer needs to adjust the duty factor to ensure that the ultrasound pulses are appropriately spaced to allow for proper imaging at the new depth. Therefore, it is true that the sonographer changes the duty factor when imaging depth is altered.
44.
What is the log of 100?
Correct Answer
B. 2
Explanation
10 x 10 = 100
45.
What is the meaning of 3dB?
Correct Answer
D. Doubled
Explanation
The meaning of 3dB is doubled. In electronics and signal processing, decibels (dB) are used to measure the ratio of two power levels. A 3dB increase represents a doubling of power or amplitude, while a 3dB decrease represents a halving of power or amplitude. Therefore, when something is described as being 3dB, it means that it has doubled in power or amplitude compared to the reference level.
46.
When the boundary is smooth, the sound is reflected in only one direction in an organized matter is called
Correct Answer
B. Specular
Explanation
When the boundary is smooth, the sound waves reflect in a specific direction in an organized manner. This type of reflection is known as specular reflection. In specular reflection, the angle of incidence is equal to the angle of reflection, resulting in a clear and focused reflection.
47.
Diffuse reflection or back scattering is when the interfaces in the body are not smooth, but have some irregularities. when a wave reflects off an irregular surface, radiates in more than one direction
Correct Answer
A. True
Explanation
Diffuse reflection or back scattering occurs when the interfaces within a body are not smooth and have irregularities. In this case, when a wave reflects off an irregular surface, it radiates in more than one direction. This means that the wave scatters or spreads out in various directions instead of reflecting in a single, focused direction. Therefore, the given answer that this statement is true is correct.
48.
The half value thickness is the distance that sound travels in a tissue that reduces the intensity of sound to one-third its original value.
Correct Answer
B. False
Explanation
intensity of sound to ONE-HALF it original value
49.
The half value layer thickness depends on which factor(s)
Correct Answer
C. Both
Explanation
The half value layer thickness depends on both the frequency of sound and the medium. The half value layer thickness refers to the distance that sound travels through a medium before its intensity is reduced by half. The frequency of sound affects the attenuation of sound waves, with higher frequencies being more easily absorbed by the medium. The type of medium also plays a role, as different materials have different absorption properties. Therefore, both the frequency of sound and the medium contribute to determining the half value layer thickness.
50.
Water has
Correct Answer
D. Extremely low
Explanation
Water has extremely low attenuation. Attenuation refers to the reduction in the intensity of a signal as it travels through a medium. In the case of water, it has a very low attenuation, meaning that it does not absorb or weaken signals passing through it to a significant extent. This property is important in various applications such as underwater communication, sonar systems, and medical imaging, where the signal needs to travel through water without significant loss or distortion.