Nature Of Sound Flashcards
It is a travelling variation in one or more quantities such as pressure. It is produced by something moving back and forth or vibrating.
Wave
What is the relationship of frequency to sound absorption?
Higher frequencies are absorbed more rapidly than lower frequencies.
Yet lower frequencies have better penetration.
It can be transmitted and produced by matter and can travel only in matter.
Mechanical wave
Motion of the particles in a medium PARALLEL to the direction of the wave propagation.
Longitudinal
Motion of the particle in the medium is PERPENDICULAR to the wave propagation.
Transverse wave
What is the relationship of the frequencies to spatial resolution?
Higher frequencies have shorter wavelength. Shorter wavelength can distinguish between reflectors thatbaremcloser together. Therefore, higher frequencies have better spatial resolution but limited penetration.
As the frequency of the UTZ increases:
The penetrability of the beam _____
Decreases
As the frequency of the UTZ increases:
The beam becomes _____
More colimated and directional
Distance between two consecutive identical positions in the wave.
Wavelength
The time it takes for one cycle to occur.
Period
Occurs when ultrasound waves of the different frequency are out of phase
Destructive Interference
Medical imaging that uses nonionizing, high frequency sound waves to generate image of a particular structure.
Sonography
As the frequency of the UTZ increases:
The ability to resolve small objects ________
Improves, increases
Relationship of period and frequency
Inversely related
Refers to the relationship of one wave to the other
Phase
It can travel either through matter or through empty space
Electromagnetic wave
Waves whose wavefronts are at the SAME position
In phase
It is the length of the space that a pulse takes up
Spatial Pulse Length
Waves whose wavefronts are at the DIFFERENT position
Out of phase
Sound is an energy transmitted as a ___________, __________ wave that requires a medium through which to travel.
Mechanical, longitudinal
What will be the result if ultrasound waves of the same frequency are in phase?
Imcreased amplitude
Increased intensity of the beam
What will be the result if ultrasound waves of the same frequency are out of phase?
Decreased amplitude
And it contributes to ultrasound attenuation
Fraction of the time that pulsed ultrasound is on
Duty Factor
It is the interaction if two or more ultrasound beams having different frequency and/or phase.
Interference
Points of zero amplitude caused by destructive interference.
Nodes
Types of ultrasound wave used in diagnostic equipments in which cycles repeat indefinitely
Continuous wave
No. of cycles per second performed by the particles in the medium in response toma wave passing through it
Frequency
It is the time from the beginning of one pulse to the next
Pulse Repitition Period
Two waves traveling in the opposite directions with the sample amplitude interfere and create a?
Standing waves
Points of maximum amplitude caused by constructive interference
Antinodes
It is the number of pulses occuring in one sec.
Pulsed Repition Frequency (PRF)
It is said that every point on a wave-front may be comsidered a source of secondary spherical wavelets which spread out in the forward direction at the speed of light. The new wave-front is the tangetial surface to all these secondary wavelets.
Huygens’ Principle
It is the time it takes for one pulse to occur
Pulse Duration
Occurs when ultrasound waves of the same frequency are in phase
Constructive Interference
Types of ultrasound wave used in diagnostic equipments in which it consists pulses separated by gaps in time
Pulsed
2 types of ultrasound waves used in diagnostic equipments
Continuous and pulsed
When two sound waves with slightly different frequencies combine.
Beat frequency
