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….
Which of the following adjustments will improve this transverse image of the upper abdomen?
1. Which of the following adjustments will improve this transverse image of the upper abdomen?
a. increase overall gain
b. decrease imaging depth
c. increase gain in the far field
d. increase gain in the near field
2. Enhancement of echo reflections occur distal to a:
a. nonspecular reflector
b. strongly reflecting structure
c. weakly attenuating structure
d. structure of high impedance
3. A change in direction of the ultrasound beam is more commonly a result of:
a. the resonance phenomenon
b. interference from multiple scatterers
c. striking a boundary at an oblique angle
d. secondary sound beams emitted from a phased array
4. Spaces between the active elements of a phased array transducer result in:
a. multipath reflections
b. the production of side lobes
c. enhancement in the focal zone
d. the production of grating lobes
5. The distance to a reflector is determined by the:
a. intensity of the returning echo
b. thickness of the imaging plane
c. time it takes for an echo to return
d. propagation speed of the medium
6. A surgical clip will most likely demonstrate which of the following artifacts?
c. comet tail
d. acoustic speckle
7. Shadowing and enhancement are a result of which type of imaging artifacts?
d. propagation speed error
b. increase imaging depth
c. increase time gain compensation in the far zone
d. increase time gain compensation in the near zone
8. What type of blood flow demonstrates a constant speed across the vessel?