What is the axial resolution in soft tissue when using a 15-MHz frequency with a two-cycle pulse?

1. Vector array is a type of transducer:

 

a. assembly

b. operation

c. construction

d. composition

2. Focusing of the sound beam is directly related to:

a. axial resolution

b. lateral resolution

c. contrast resolution

d. elevation resolution

3. Steering of the sound beam is accomplished by:

a. constructive interference

b. focusing of the sound beam

c. increasing the resonant frequency

d. altering the excitation of the active elements

4. Exceeding the Curie point of a transducer element will result in:

a. a broader bandwidth

b. a higher propagation speed

c. a higher operating frequency

d. the loss of all piezoelectric properties

5. An active element with a thickness of 0.8 mm and a propagation speed of 4 mm/ms will have an operating frequency of:

a. 2.5 MHz

b. 3.5 MHz

c. 4.0 MHz

d. 5.0 MHz

6. What is the thickness of the crystal with an oper­ating frequency of 5.0 MHz and a propagation speed of 4 mm/ms?

a. 0.1 mm

b. 0.2 mm

c. 0.3 mm

d. 0.4 mm

7. Temporal resolution is determined by the:

a. medium

b. frame rate

c. beam width

d. element thickness

8. What is the axial resolution in soft tissue when using a 15-MHz frequency with a two-cycle pulse?

a. 0.1 mm

b. 0.3 mm

c. 0.4 mm

d. 0.55 mm

9. Which of the following transducers operates by applying voltage pulses to groups of linear elements in succession?

a. vector array

b. linear phased array

c. convex phased array

d. linear sequenced array

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