What is the operating frequency of a two-cycle pulse with an element thickness of 0.2 mm and a propagation speed of 4 mm/ms?

1. Snell’s law determines the amount of:

 

a. reflection at an interface

b. refraction at an interface

c. transmission through a medium

d. scattering distal to a dense medium

2. Direction of the incident beam with respect to the media boundary is termed the:

a. specular angle

b. reflection angle

c. propagating angle

d. transmission angle

3. Demonstration of boundaries between organs is a result of:

a. refraction

b. transmission

c. specular reflection

d. Rayleigh scattering

4. What is the penetration depth of a 3.5-MHz frequency when imaging the abdominal aorta?

a. 0.86 cm

b. 1.71 cm

c. 0.86 mm

d. 1.75 mm

5. With perpendicular incidence, the larger the imped­ance difference between the media, the greater the:

a. scattering

b. reflection

c. absorption

d. transmission

1. Widening of the sound beam is demonstrated in the:

a. focal point

b. focal zone

c. Fresnel zone

d. Fraunhofer zone

2. Weak beams emitted from a linear sequenced array transducer are termed:

a. side lobes

b. harmonics

c. grating lobes

d. mechanical waves

3. The resonant frequency of a pulse wave is determined by the:

a. diameter of the beam

b. impedance of the matching layer

c. electrical frequency of the ultrasound system

d. thickness and propagation speed of the element

4. Heat sterilization is not recommended for diagnostic transducers because:

a. apodization will occur

b. the housing may be damaged

c. the epoxy in the backing will melt

d. the piezoelectric properties will be lost

5. Which of the following components is unneces­sary in the construction of a continuous wave transducer?

a. matching layer

b. damping layer

c. electrical wiring

d. two active elements

6. Lateral resolution is determined by the:

a. beam width

b. near-zone length

c. spatial pulse length

d. thickness of the active element

7. What is the axial resolution in soft tissue when using a 5.0-MHz frequency with a two-cycle pulse, and an element thickness of 0.5 mm?

a. 0.3 mm

b. 0.5 mm

c. 0.6 mm

d. 0.8 mm

8. What is the operating frequency of a two-cycle pulse with an element thickness of 0.2 mm and a propagation speed of 4 mm/ms?

a. 3.5 MHz

b. 5.0 MHz

c. 7.5 MHz

d. 10.0 MHz

9. On which of the following principles do diagnostic ultrasound transducers operate?

a. Snell’s law

b. ALARA principle

c. Huygens principle

d. piezoelectric effect

10. If the width of the transducer is 5.0 cm, what is the width at the focal point?

a. 1.0 cm

b. 2.5 cm

c. 5.0 cm

d. 10.0 cm

11. Constructive interference will create a wave with amplitude:

a. equal to the original waves

b. less than the original waves

c. shorter than the original waves

d. greater than the original waves

 

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