question

1. An ultrasound beam passing through the body

a is attenuated

b produces heating of tissues

c can be reflected

d produces ionization

2. Ultrasonic pulses

a are poorly transmitted by liquids

b are poorly transmitted by air gaps

c are partially reflected at interfaces between two liquid media

d are partially transmitted at interfaces between two solid media

3. The Fraunhofer zone is the

a image plane

b image focus

c near field

d far field

4. Which of the following statements are true concerning the nature of diagnostic ultrasound in liver?

a The wave speed and frequency are constant regardless of the wavelength

b The wave speed is constant regardless of the wavelength

c Wave speed increases with the increasing frequency

d None of the above

5. Which of the following characteristics of diagnostic ultrasound applies also to X-radiation?

a It is a wave phenomenon

b Its wave speed and frequency are inversely proportional

c Matter must be present for transmission

d Molecular compression and rarefaction occur