Quiz Exam 2- Ultrasound Physics: Waves (Parameters And Variables)

Hertz is a unit used to measure frequency, specifically the number of cycles or oscillations per second. Decibels measure the intensity or loudness of sound, watts measure power, and milliseconds measure time. Therefore, Hertz is the correct answer as it is the unit that specifically measures frequency.

The given statement defines bioeffect as the impact of mechanical waves, specifically sound, on living tissue. This suggests that bioeffect refers to the effects that sound waves have on living organisms. Therefore, the statement is true.

The correct answer is 1540. This refers to the propagation speed of sound waves in soft tissue. Sound travels at different speeds through different materials, and in soft tissue, such as muscles or organs, the speed is approximately 1540 meters per second. This speed is important in medical imaging techniques such as ultrasound, where sound waves are used to create images of internal structures. By knowing the propagation speed, accurate measurements and imaging can be achieved.

The original beam is also known as the incident beam because it refers to the beam of light or radiation that is initially directed towards a surface or object. This term is commonly used in physics and optics to describe the beam before it interacts with the surface or object.

The correct answer is "Directly." This suggests that there is a direct relationship between power and intensity. In other words, as power increases, intensity also increases. This implies that the two variables are positively correlated, meaning that when one variable increases, the other variable also increases.

Attenuation is the correct answer because it refers to the loss of energy in sound waves during propagation through a medium. This loss of energy causes the waves to lose distance, frequency, and amplitude. Attenuation can occur due to factors such as absorption, scattering, and dispersion. It is an important phenomenon to consider in various applications of sound, such as in telecommunications and underwater acoustics.

The correct answer is "Directly" because stiffness and speed of sound are directly related. This means that as the stiffness of a material increases, the speed of sound through that material also increases. Similarly, if the stiffness decreases, the speed of sound will also decrease. Therefore, there is a direct correlation between the two variables.

The relationship between frequency and period is inverse. This means that as the frequency of a wave increases, the period decreases, and vice versa. Frequency refers to the number of complete cycles of a wave that occur in a given time, while period is the time it takes for one complete cycle to occur. As the frequency increases, the time it takes for each cycle to occur decreases, resulting in a shorter period. Conversely, if the frequency decreases, the period becomes longer.

Increasing stiffness in a system leads to increased speed because stiffness refers to the resistance of an object to deformation. When an object is stiffer, it can withstand greater forces without deforming, allowing it to move faster. This is because the increased stiffness provides a stronger and more stable structure, enabling quicker and more efficient motion. On the other hand, if stiffness is decreased, the object becomes more flexible and prone to deformation, resulting in decreased speed.

The correct answer is "Watts/cm²" because intensity is a measure of power per unit area. Watts is the unit of power, and cm² is the unit of area. Therefore, when measuring intensity, the unit is expressed as watts per square centimeter (Watts/cm²) to indicate the amount of power distributed over a specific area.

The given statement is false because the formula for power is not A cubed. The correct formula for power is P = A^2, where A represents the amplitude of the wave. Therefore, the correct answer is False.

The statement "Period is not adjustable" means that the period, which refers to a specific length of time, cannot be changed or modified. This implies that the period remains constant and cannot be altered according to any external factors or preferences. Therefore, the correct answer is "True" as it confirms that the period is indeed not adjustable.

The correct answer is "Directly" because when two variables are said to be directly related, it means that as one variable increases, the other variable also increases. In this context, when we talk about amplitude and power, an increase in amplitude will result in an increase in power. Therefore, amplitude and power are directly related.

Mechanical waves are waves that require a medium to propagate. They cannot travel through a vacuum because they rely on the particles of the medium to transfer energy. Therefore, the correct answer is "Medium only".

The statement "Period is determined by sound source only" is true. The period of a sound wave refers to the time it takes for one complete cycle of the wave to occur. It is solely determined by the frequency of the sound source, which is the number of cycles per second. The sound source itself, such as a vibrating object or an instrument, determines the frequency and therefore the period of the sound wave it produces. Other factors like the medium through which the sound travels may affect the speed or intensity of the wave, but they do not directly impact the period.

The term "inversely" suggests that there is a relationship between period and frequency where one increases while the other decreases. In the context of waves or oscillations, period refers to the time it takes for one complete cycle, while frequency represents the number of cycles that occur in a given time. Since these two quantities are inversely related, as the period increases, the frequency decreases, and vice versa.

When the density of an object or substance increases, its speed decreases. This is because an increase in density means that there are more particles packed closely together, resulting in more collisions and interactions between the particles. These collisions and interactions create resistance and friction, which slows down the movement of the object or substance. Therefore, when density increases, the speed decreases.

The correct answer is "Directly." This means that there is a direct relationship between amplitude and intensity. As the amplitude increases, the intensity also increases. Similarly, as the amplitude decreases, the intensity also decreases.

The correct answer is "ms/s" because it represents the units for propagation speed, which is the rate at which a wave travels through a medium. The abbreviation "ms/s" stands for meters per second, indicating that the wave travels a certain distance in meters within one second. This unit is commonly used to measure the speed of sound or electromagnetic waves.

The propagation speed of air refers to the speed at which sound waves travel through air. In this case, the correct answer is 330, which is likely referring to the speed of sound in meters per second at standard temperature and pressure. This value is commonly used as an approximation for the speed of sound in air.

Depolarization refers to the process of reducing or reversing the polarization of a cell or membrane. In this context, destructive depolarization implies that the depolarization is causing damage or harm. This could be in reference to depolarization in neurons, where excessive or uncontrolled depolarization can lead to cell death or neurological disorders. Therefore, the correct answer "Destructive" suggests that depolarization in this scenario is causing negative consequences or harm.

The given answer "Millimeters" is the correct unit for wavelength. Wavelength is a measure of the distance between two consecutive points in a wave, typically measured in meters or its subunits. Millimeters is a subunit of meters and is commonly used to measure small distances. Therefore, millimeters is an appropriate unit to measure the wavelength of a wave.

The given frequency range of 2-10 MHz is typically used for ultrasound imaging. This range is suitable for medical applications as it allows for better resolution and imaging of soft tissues. Higher frequencies provide finer detail and better resolution, which is important for visualizing small structures and detecting abnormalities. In contrast, lower frequencies are used for deeper penetration and imaging larger structures. Therefore, the frequency range of 2-10 MHz is commonly used in medical ultrasound imaging for its ability to provide good resolution and depth penetration.

The relationship between wavelength and frequency is inversely proportional. This means that as the wavelength increases, the frequency decreases, and vice versa. This can be explained by the wave equation, which states that the speed of a wave is equal to the product of its wavelength and frequency. Since the speed of a wave is constant, if one variable increases, the other must decrease to maintain the same speed. Therefore, wavelength and frequency have an inverse relationship.

Absorption is the dominant form of attenuation because it refers to the process where energy of a wave is absorbed by the medium through which it is passing. This results in a decrease in the intensity of the wave. Unlike reflection, refraction, and scattering, which involve the redirection or dispersion of the wave, absorption involves the conversion of the wave's energy into other forms, such as heat. Therefore, absorption is the primary mechanism by which the intensity of a wave diminishes as it travels through a medium.

The statement is false because the only difference between sterilization and disinfection is not the additional use of pressure. Sterilization refers to the complete elimination of all microorganisms, including bacteria, viruses, and spores, from an object or surface. It can be achieved through various methods such as heat, chemicals, or radiation. Disinfection, on the other hand, refers to the reduction of microorganisms to a level that is considered safe for public health. It does not necessarily eliminate all microorganisms or spores. Pressure is not a defining factor in distinguishing between sterilization and disinfection.

Constructive polarization refers to the alignment of electromagnetic waves in a specific direction. When waves are in phase and their electric fields are aligned, they reinforce each other, resulting in a stronger and more focused wave. This alignment is known as constructive polarization. It is the opposite of destructive polarization, where waves are out of phase and cancel each other out. In this case, the correct answer is "Constructive" because it accurately describes the process of alignment and reinforcement of waves.

The given correct answer, "Inversely," suggests that there is an inverse relationship between acoustic velocity and density. This means that as one variable increases, the other variable decreases, and vice versa. In other words, when the density of a medium increases, the acoustic velocity decreases, and when the density decreases, the acoustic velocity increases. This relationship is important in understanding how sound waves travel through different materials, as the density of a medium affects the speed at which sound can propagate through it.

Decibels are a unit used to measure the intensity or power level of sound. It is a logarithmic scale that compares the sound pressure level to a reference level. Decibels are commonly used in acoustics and audio engineering to express the loudness or volume of sound. It is not a unit of amplitude, which typically refers to the maximum displacement or variation in a wave. Pascals are the units for measuring pressure, watts for power, and hertz for frequency.

During compression, the pressure exerted on a substance increases, causing the molecules to be pushed closer together. This results in an increase in density, as the same amount of matter is now occupying a smaller volume. Therefore, the correct answer is "Increased pressure, increased density."

PZT stands for Lead Zirconate Titanate, which is a piezoelectric material used in various applications. The term "Pulsing" is not related to the acronym PZT and does not stand for it.

Temperature is inconsequential to clinical ultrasound because it does not directly affect the performance or interpretation of ultrasound imaging. Unlike pressure, density, and particle motion, temperature does not impact the propagation of sound waves through tissues. The speed of sound in tissues is mainly determined by the density and elasticity of the medium, while temperature has a minimal effect on these properties. Therefore, variations in temperature within the normal range do not significantly affect the accuracy or quality of clinical ultrasound imaging.

The correct answer is 4000. Bone has a propagation speed of 4000. This means that sound waves travel through bone at a speed of 4000 meters per second.

The relationship between elasticity and speed of sound is inversely proportional. This means that as the elasticity of a medium increases, the speed of sound in that medium decreases, and vice versa. Elasticity refers to the ability of a material to deform under stress and then return to its original shape when the stress is removed. In the context of sound waves, a more elastic medium will allow the sound waves to propagate faster, while a less elastic medium will slow down the speed of sound. Therefore, the two variables are inversely related.

Absorption increases exponentially with an increase in frequency because as the frequency of a wave increases, the energy of the wave also increases. This increase in energy leads to more absorption of the wave by the medium it is passing through. Therefore, the absorption of a wave is directly proportional to its frequency, resulting in an exponential increase in absorption with an increase in frequency.

The given answer "None" suggests that there is no relationship between wavelength and intensity. This means that as the wavelength of a wave changes, the intensity does not change in a predictable or consistent manner. In other words, the two variables are independent of each other and do not affect each other.

The relationship between power and frequency is described as "None" in this context. This means that there is no direct or inverse relationship between power and frequency. The two variables are independent of each other and do not affect one another.

The reverse piezoelectric effect occurs during transmission. This effect is observed when an electric field is applied to a piezoelectric material, causing it to deform and generate mechanical vibrations or waves. In the context of transmission, this effect is utilized to convert electrical signals into mechanical waves, which can then be transmitted through a medium such as air or water. Therefore, the correct answer is "During Transmission."

During rarefaction, the pressure of a medium decreases, which means that the particles in the medium are moving further apart. This results in a decrease in density because there are fewer particles in a given volume. Therefore, the correct answer is "Decreased pressure, decreased density."

The given answer "None" suggests that there is no relationship between frequency and intensity. In other words, the two variables are not connected or influenced by each other. This means that as the frequency increases or decreases, the intensity does not change, and vice versa.

The given answer correctly identifies the three types of scattering as Regular, Backscattering, and Rayleigh. Regular scattering occurs when the scattered waves are in phase and create a well-defined pattern. Backscattering refers to the scattering of waves directly back towards the source. Rayleigh scattering occurs when the size of the scattering particles is much smaller than the wavelength of the incident waves, resulting in scattering in all directions.

The correct answer is 1-3 MPa. The amplitude is a measure of the maximum displacement or distance from the equilibrium position in a wave. In this context, it refers to the maximum pressure variation in a sound wave. The given range of 1-3 MPa represents the typical values for the amplitude of sound waves, indicating the pressure fluctuations can range from 1 to 3 million pascals.

The sonographer is able to adjust the intensity, power, and amplitude during an ultrasound examination. Intensity refers to the strength or power of the ultrasound beam, which can be adjusted to control the level of energy delivered to the body. Power is the rate at which energy is delivered, and the sonographer can adjust it to control the strength of the ultrasound beam. Amplitude refers to the maximum displacement of a wave from its equilibrium position, and the sonographer can adjust it to control the strength of the ultrasound signal.

The relationship between acoustic velocity and compressibility is that they are inversely proportional. This means that as the compressibility of a medium increases, the acoustic velocity decreases, and vice versa. In other words, when a medium is more compressible, it takes more time for sound waves to travel through it, resulting in a lower acoustic velocity. Conversely, when a medium is less compressible, sound waves can travel through it more quickly, resulting in a higher acoustic velocity.

The question is asking about the relationship between the angle and the speed. If the speed is faster, it means that the object is moving at a higher rate. When an object moves faster, it covers a greater distance in a given amount of time. This results in a larger angle being formed as the object moves through a greater distance. Therefore, the angle is bigger when the speed is faster.

The answer is microseconds because it is a unit of time that is smaller than seconds but larger than milliseconds. It is commonly used to measure very small durations of time, such as the delay between electronic signals or the response time of computer systems.

Electromagnetic waves can exist in both a medium and a vacuum. In a medium, such as air or water, electromagnetic waves can travel by causing the atoms or molecules in the medium to vibrate. In a vacuum, electromagnetic waves can still propagate because they do not require a physical medium to travel through. This is because electromagnetic waves are composed of oscillating electric and magnetic fields, which can travel through empty space without the need for a material medium. Therefore, electromagnetic waves can exist in both a medium and a vacuum.