Physics 111 Chapter 2 Flashcards
A wave is a traveling variation in quantities called wave________________
variables
Ultrasound is sound with a frequency greater than
20,000
Ultrasound is sound with a frequency greater than
20,000 Hz
______________ is the time it takes for one cycle to occur.
Time
Wavelength is the length of _____________ over which one cycle occurs.
Space
Sound requires a ______________ through which to travel.
Medium
Stiffer media have _______________ sound speeds
Higher
Propagation speed is primarily determined by the ______________ of the medium.
Stiffness
Ultrasound pulses contain a range of frequencies called the _______________.
Bandwidth
Regions of lower pressure and density are called
rarefactions
________________ area even and odd multiples of the fundamental frequency
Harmonics
Doppler ultrasound pulses are typically _________ cycles long
5-30
The fraction of time that pulsed ultrasound is on is called
Duty Factor
The rate at which energy passes through a unity area is called
Intensity
As sound travels, the reduction of amplitude and intensity of the wave is called
attenuation
The average propagation speed in human soft tissue is ________________
1540m/s
If you switch to a lower frequency for penetration, the wavelength of the transducer ______________
Increases
1000 Hz is equal to _______________ kHz
1
If the beam power increases, intensity ___________________
Increases
If the beam area decreases, the intensity ___________
Increases
Attenuation increases with increasing ___________
Frequency
For perpendicular incidence, the incidence angle is______________
0
The ______________ _____________ is the number of pulses that occur in single second
Pulse repetition frequency
If the number of cycle in a pulse is reduced, the pulse duration _______________
is decreased