At what depth will a 3.0-MHz frequency demon­strate an attenuation of 9 dB?

1.In perpendicular incidence, what percentage of the sound wave will reflect at a boundary if the impedance of medium 1 is 40 rayls and the impedance of medium 2 is 50 rayls?

 

a. 1%

b. 10%

c. 75%

d. 90%

2. Bending of a transmitting sound beam after it passes through one medium into another describes:

a. scattering

b. refraction

c. reflection

d. reverberation

3. Attenuation is most commonly a result of:

a. reflection

b. scattering

c. absorption

d. transmission

4. Half value layer is equal to an intensity reduction of:

a. 3 dB

b. 6 dB

c. 10 dB

d. 50 dB

5. Propagation speed is directly related to:

a. density

b. stiffness

c. frequency

d. wavelength

6. Which of the following is proportional to the impedance of a medium?

a. wavelength

b. propagation speed

c. stiffness of the medium

d. attenuation coefficient

7. Which of the following units compares the ratio of amplitudes along two points of a sound wave?

a. W

b. dB

c. rayl

d. dB/cm

8. Attenuation of the sound beam is proportional to the:

a. frequency of the sound wave

b. direction of the incident beam

c. reflected intensity of the sound wave

d. transmitted intensity of the sound wave

9. Which of the following is responsible for deter­mining the amount of reflection and transmission of the sound wave?

a. density

b. stiffness

c. impedance

d. propagation speed

10. Dissipation of heat in a medium primarily in the form of heat describes:

a. reflection

b. refraction

c. absorption

d. half value layer

11. At what depth will a 3.0-MHz frequency demon­strate an attenuation of 9 dB?

a. 2 cm

b. 3 cm

c. 6 cm

d. 9 cm

 

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