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Physics Frequency
Physics Frequency Quiz
Question | Answer |
---|---|
What determines frequency? | The thickness of the crystal |
What is the frequency with a thin crystal? | High |
What is the frequency with a thick crystal? | Low |
What is the behavior of the frequency of a wave as it travels through different media? | It remains unchanged |
What is the relationship between period and frequency? | Inverse |
What is the relationship between wavelength and frequency? | Inverse |
What is the relationship between propagation speed and frequency? | Unrelated (Wavelength & Velocity are related to propagation speed) |
What is the effect of frequency on image quality? | Direct - Higher frequency = better resolution |
What is the effect of frequency on depth of penetration? | Inverse - Higher frequency = less depth of imaging |
What determines the period of an ultrasound wave? | Wavelength frequency which is determined by the thickness of the crystal in the transducer |
What is the formula for frequency? | F = 1/T or F = V/wavelength |
Define frequency - | The number of particular events ( /cycles or pressure oscillations) that occurs in a specific duration of time; |
Frequency is reported in what units? | Units per second or hertz. (Hz) |
How would you write 1,000 hertz? | 1 kHz (Kilohertz) |
How would you write 1,000,000 hertz? | 1 MHz (megahertz) |
What are the typical values of frequency used in clinical imaging? | 1 MHz to 10 MHz or 1 million to 10 million per second |
Frequency is determined by? | Sound source not the medium through which the sound is traveling |
How can the frequency be adjusted by the sonographer? | By changing the tranducer (The thinner, the higher) |
Define audible - | Sounds that humans can hear (Sounds between 20 Hz and 20,000 Hz) (20,000 Hz = 20 kHz) |
Define infrasonic - | Sound waves below 20 Hz |
What happens to period when frequency increases? | Period decreases |
What is the frequency of ultrasound? | Greater than 20 kHz |
What is the second, even more special, relationship between period and frequency? | They are reciprocals |
What does it mean when two parameters are reciprocals? | When the two parameters are multiplied together, the answer is always 1 |
Example of the reciprocal relationship between period and frequency - | If a wave takes 1/8 of a second to vibrate up & down the period is 1/8 & the frequency is 8 per second or 8 Hz |
What is the fundamental measurement of velocity? | Most common: 1.54 x 10 ^3 M/sec - Can use: 60 miles/min or 3600 mph |
What is the range for perios (T)? | 0.1 to 1 microsecond |
What is the relationship between depth of penetration and frequency? | Inverse |
What is the relationship between rate of attenuation and frequency? | Direct |
What is the relationship between quality/spatial resolution and frequency? | Direct |
If given period, and you want to solve for frequency. What do you use? | Period to Frequency - Use F = 1/T |
If given frequency, and you want to solve for period. What do you use? | Frequency to Period - Use T = 1/F |
Given wavelength, and you want to solve for frequency. What do you use? | Wavelength to Frequency - Use F = V/Wavelength |
Given frequency, and you want to solve for wavelength. What do you use? | Frequency to wavelength - Use Wavelength = V/F |
Sound is what kind of wave? | Mechanical & Longitudinal |
Density, particle motion & pressure are considered examples of what? | Acoustic variables |
The effect of ultrasound upon tissue is called what? | Bioeffects |
The product of wavelength X frequency is what? | Velocity |
M/cycle X cycle/second = what? | M/second |
What happens to frequency when the period doubles? | It halves |