Acoustic physics review ch 1-3
The poll's duration is one millisecond and the pulse Repetition period is 1 second.The duty factor is
0.1%
1,000,000=
1.0 x 10^6 106
0.000000124=
1.24 x 10^-7
1742=
1.742 x 10^3
How much bigger is a giga- than a kilo-
1/1,000,000
The speed of sound in soft tissue
1540 m/s or (1.54 mm/us)
How many milliliters are in three point 3.87 liters
3,870
Transducer travels through Air
330 m/sec
bone is
3500 m/sec
A 6MHZ Continuous wave has a propagation speed of 6km/s. The wave is then pulsed with a duty factor of 0.5. The New propagation speed is
6km/s
Piezoelectric effect
Converting one form of energy into another from an electrical wave to a mechanical wave upon transmission reception is from mechanical to electricals
audible sound
The range of human hearing between 20Hz- 20,000hz or 20Hz-20khz
Waves propagate from place to place by
Transfer of energy
Peak measurements of intensity are lower than the average measurement
false
intensities have Different measurements to help in the study of the bio effects of ultrasound
false
Which of the following Is in correct order from largest to smallest
giga,mega,kilo,centi
Which of the following is incorrect order from smallest to largest
micro,killo,mega
If I begin an exam using a 2.0 MHz transducer and the next exam requires using a 7.0MHZ transducer, what will happen to my period? wavelength?
they decrease
What is the relationship between frequency and waveling
they have an inverse relationship ( We see better because we are closer to the structure)
axis of waveform
time and amplitude perpendicular
Pulse repetition frequency and pulse repetition period are directly proportional to each other
true
Units for intensity are
watts/sq-cm
in phase waves
when the peaks (maximum values) and troughs (minimum values) of a pair of waves occur at the same time and at the same location
What is the relationship between frequency and axial resolution
direct (meaning an increase in frequency or high frequency(5.0,7.0,10.0) Will increase axial resolution
definition of sound
A longitudinol mechanical wave
Transverse waves
A wave in which the particles of the medium move perpendicularly to the direction the wave is traveling
Ultrasound
Above the audible range of human hearing ultrasound is above 20khz or 20,000hz
Some waves are. Identified by three
Acoustic variables
Sound waves are characterized by seven
Acoustic variables
Infrasound
Below the audible range of human hearing and for sound is below 20hz
frequency of 2.0-2.5 are?
Deep structures increasing the depth and decreasing the axial resolution
Which of the following is not an acoustic parameter
Density
Molecules in the media through which a sound wave propagates vibrate in the direction of propagation
False
Sound waves are typically transverse waves
False
frequency 5.0-7.0-10.0 are
For surface structures that decrease the depth and increase the axial resolution
Constructive interference
In faceway from a single wave of greater amplitude than either of its components the resulting wave is larger
Destructive interference
Out of phase way from a single wave of lesser amplitude than at least one of its components. Resultant wave is smaller.
Out of face waves
Peak Occur at different times
Formula for propagation Speed
Speed (m/s) = frequency (Hz) x wavelength (m) mm=1.54mm/us
How do I change my amplitude and intensity
Use output power
Formula for wavelength
Wavelength = speed/frequency
When using high frequency resolution aka: ( superficial, surface structures, our bean scanned).
You receive less death penetration but improve axial resolution. "we see better because we are closer"
How much smaller is a nano than a milli
a million times
longitudinal wave
a wave in which the particles of the medium vibrate parallel to the direction of wave motion.
What are seven acoustic parameters
period, frequency, amplitude, power, intensity, wavelength, propagation speed
Formula for frequency
speed/wavelength
