Week 1 exam Flashcards
Sound can travel through all of the following except:
A vacuum
An interaction of echoes that leads to reinforcement rather that to partial or total cancellation is known as:
Constructive interference
On a diagram of a waveform, the peak above the baseline represents
Compression
When you switch from a 2.5 MHz to a 5 MHz transducer, the sound wavelength:
halves
The amount of a space within a specific boundary defines:
area
What sound parameter is determined only by the medium?
Propagation speed
If the frequency is increased, the __ will be __
velocity; unchanged
A wave vibration at 20 cycles per second has a frequency of:
20 Hz
For every increase of one in the powers of ten, the decimal point:
shifts one space to the right
Which of the following is required for the answer to a numerical question to be comprehensive?
Units
Proportionally related means:
two items are related, but the relationship is not specific
Density is defined as:
mass per unit of volume
How would the number 0.000001 be represented using scientific notation?
1.0x10^-6
Which prefix equals 10^-3
milli
Which of the following represents the number 1234 in scientific notation?
1.234x10^3
Sound waves can go through a vacuum if the amplification is high enough
false
The term compression zone describes a region of ___ in the medium, which is subjected to an ultrasound field
increased molecular density
The definition of period of a wave cycle is
time for one complete cycle to occur
Which of the following tissues are in order of propagation speed from fastest to slowest?
bone, blood, lung
Ultrasound waves are best described as:
high-frequency longitudinal mechanical waves
In scientific notation, a number with positive exponent has a value:
greater than one
When waves combine to form a single wave of less amplitude, it is called:
destructive interference
If the period decreases, the wavelength
decreases
The sound wave from which frequency transducer travel faster in soft tissue?
they all travel the same speed
As frequency increases,
propagation speed does not change
Directly related means:
when one item increases or decreases, the second item responds the same direction
The formula for intensity is
1 = power/area
10^-3 equals:
1/1000
What would the following sequence be in scientific notation? Milli, Kilo, Mega, Centi?
10^-3, 10^3, 10^6, 10^-2
Waves transfer ___ from one location to another
energy
What term is the reciprocal of Mega?
micro
Which are appropriate complementary units
mega and micro
Which of the following acoustic variables will change due to sound travel through a medium?
pressure
The positive half of a pressure wave corresponds to:
compression
Which of the following best equates to the value 7,500,000 Hz?
7.5 MHz
Two waves arrive at a location at the same time. What event takes place?
interference
Which of the following is not an acoustic parameter?
pressure
What does compression and rarefaction change in the medium?
density
Which of the following is NOT the average value for propagation speed
1.54 mm/s
If the power is doubled, and the area remains the same, intensity is ___
doubled
Two quantities are proportional if an increase in one quality leads to a/an ___ in the other
increase
Circumferences are usually measured in:
cm
Which of the following is defined as force per unit area?
pressure
Bulk modulus is closely related to which of the following qualities?
stiffness
Which has the slowest propagation speed?
lung
If the power of a wave is increased by a factor of 10, what happens to the intensity of the wave?
it increases by a factor of 10
If the period of a wave is increased by a factor of 2, what happens to the propagation velocity?
propagation velocity remains unchanged
Intensity can be adjusted by the sonographer
true
Which of the following bests describes ultrasound?
A mechanical vibration transmitted through a medium as a longitudinal wave
Characteristics & features describing an ultrasound wave include:
Compression/ rarefraction
longitudinal
mechanical
The number 10^3 is the same as:
one thousand
Which sound waves are audible?
10 kHz
Which of these ranges of frequencies would be considered for diagnostic ultrasound?
4 to 10 MHz
If the propagation speed increases, with ___ stiffness
increased
The maximum cyclical variation or change in a quantity of an acoustic variable, such as pressure, is known as___
amplitude
The highest level of concentration of molecules in a wave is called
compression
If the frequency of a sound wave is 5 Hz, the period will be:
1/5 second
As sound travels through a medium, what term describes the effects of the medium on the sound wave?
Acoustic propagation properties
Which of the following is equivalent to the prefix giga?
109
The speed of sound traveling through soft tissue is:
1540 m/s
A sonographer measures the perimeter of an anatomical structure. Which of the following choices is a reasonable value for the measurement?
15 mm
If the amplitude of a wave doubles, the intensity will:
quadruple
If transducer frequency remains constant but wavelength was shown to increase, which of the following is correct?
propagation velocity increased
The formula for wavelength is
propagation speed / frequency
Which of the following correctly defines acoustic frequency?
number of cycles in a second
If frequency increases, wavelength
decreases
Which of the following terms does not belong with the others?
wider molecular spacing
What happens to the frequency of a sound wave if the wavelength is increased by a factor of 5?
frequency decreases by a factor of 5
If two variables are inversely proportional, if one decreased by a factor of 5, then the other
increased by a factor of 5
Density and propagation speed are
inversely related
Diagnostic frequencies range between:
2.0 and 15.0 MHz
If the ares is doubled, and the power remains the same, intensity is ___
halved
Volume has which of the following units
Cm^3
Inversely related means:
items are related as that the change in one creates an opposite change in the other
Which of the following best describes direction of motion of the particles in a sound wave?
particle motion is parallel to the direction in which the waves are traveling
