Chapter 3: describing sound waves Flashcards
Define Parameters
describe features of a sound wave.
what the seven paramets are used for?
they are values used to characterize a sound wave
list the seven parameters
PERIOD
FREQUENCY
INTENSITY
POWER
AMPLITUDE
WAVELENGTH
PROPAGATION SPEED
PETER
FELL
IN
PRACTICE
AFTER
WAVING
(AT) SALLY
PERIOD
FREQUENCY
INTENSITY
POWER
AMPLITUDE
WAVELENGTH
SPEED
source
the transducer and the ultrasound system
medium
soft tissue
period
Define
the time it takes a wave to vibrate a single cycle.
the time from the start of one cycle to the start of the next.
period
Units for period
time (seconds,microseconds
what is period determined by?
the sound source only
is period adjustable?
no
What are the seven acoustic parameters?
Frequency
period,
wavelength,
propagation of speed,
intensity,
amplitude
and power.
Frequency
the number of events that occur in a specific duration of time
in diagnostic ultrasound, the frequency of a wave is described as
the number of cycles that occur in one second
Unit for frequency
per seconds, 1/second, hertz, Hz
Hertz is another way to say
per second
Is frequency adjustable?
no
what is frequency determined by?
the sound source only
frequency for infrasound
less than 20 Hz
frequency for ultrasound
greater than 20 kHz or 20,000 Hz
frequency for audible
Between 20Hz and 20 kHz
frequency for diagnostic ultrasound
1MHz to 20MHz
Why is frequency important?
It affects the penetration and image quality
What is the relationship between period and frequency?
Period and frequency are inversely related to each other
As frequency increases, period____
decreases
As frequency decreases, period____
increases
Period and Frequency have a special relationship called….
Reciprocal
Formula for period and frequency
period x frequency =1
A wave takes up 1/8 of a second to vibrate up and down. What is the period and the frequency?
Period = 1/8
Frequency = 8
1/8x8=1`
The higher the frequency
the lower the period
which of the following waves is infrasonic?
4 Mhz
400 kHz
28 Hz
2 Hz
2 Hz
less than 20Hz cannot be heard
which wave is ultrasonic?
400 mHz
4 MHz
28 Hz
2 Hz
4 MHz
greater than 20kHz cannot be heard
indetify all which are audiable
4 MHz
400 kHz
28 Hz
2 Hz
4 MHz, 400kHz,2 Hz are all audiable
which of the following has the longest period
2MHz
4,000 Hz
6 Hz
1 kHz
6Hz
which has the highest frequency
8 s
80 µseconds
8 Ms
8000 ks
8 µseconds
The three bigness parameters
IPA
intensity
power
amplitude