1. (a) Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator: (i) series-connected, (ii) shunt-connected and (iii) compound-connected. (b) State one purpose for which….
What is the minimum number of memory bits necessary to display 128 shades of gray?
1.. A disadvantage of duplex imaging is a(n):
a. decrease in imaging frame rate
b. inability to display peak velocities
c. inability to demonstrate flow direction
d. decrease in maximum penetration depth
2. Which of the following transducers will produce a longer focal length if the crystal diameter remains constant?
a. 5-MHz focused transducer
b. 10-MHz focused transducer
c. 5-MHz unfocused transducer
d. 10-MHz unfocused transducer
3. The duty factor in pulse ultrasound is proportional to the:
a. pulse duration
b. penetration depth
c. operating frequency
d. pulse repetition period
4. Depth gain compensation is necessary to:
a. counteract attenuation
b. increase axial resolution
c. decrease contrast resolution
d. store echo amplitudes and locations
5. The Reynolds number predicts the onset of:
b. turbulent flow
c. a Doppler shift
d. biological effects
6. Which of the following types of resolution does the wavelength have the greatest effect on?
7. The objective of the matching layer in the assembly of an ultrasound transducer is to reduce the:
a. pulse duration
b. spatial pulse length
c. number of cycles in each pulse
d. impedance difference between the element and skin
8. What is the minimum number of memory bits necessary to display 128 shades of gray?
9. Which of the following is a function of read zoom?
a. frame averaging
b. magnification and display of stored data
c. acquisition and magnification of new information
d. increase in the number of pixels per inch
10. Averaging the frame rate is operator adjustable using which of the following functions?
a. read zoom
c. dynamic range
d. contrast variation
11. At a stenosis, pressure will:
d. remain unchanged