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 properties is proportional to the pulse repetition frequency?
1. Spatial is a term used to describe:
2. Which of the following units measures the attenuation of sound in soft tissue?
3. If the frequency is increased, pulse duration will:
d. remain unchanged
4. Which of the following metric prefixes denotes 1 billion?
5. Which of the following units of measurement represents the number of pulses occurring in 1 second?
6. Which of the following formulas determines the impedance of a medium?
a. attenuation multiplied by the propagation speed of the medium
b. propagation speed of the medium multiplied by the round-trip time
c. density of the medium multiplied by the attenuation coefficient
d. density of the medium multiplied by the propagation speed of the medium
7. Weakening of a sound wave as it travels through a medium defines:
d. acoustic impedance
8. Which of the following occurs when a sound wave strikes a large, smooth surface at a 90° angle?
b. specular reflection
c. Rayleigh’s scatter
d. nonspecular reflection
9. With perpendicular incidence, what percentage of the incident beam continues to the next medium?
10. The unit of measurement used to describe the amplitude of a pressure wave is:
11. Which of the following properties is proportional to the pulse repetition frequency?
b. duty factor
c. penetration depth
d. spatial pulse length
12. Which of the following will most likely decrease the propagation speed of a wave?
a. increasing the penetration depth
b. increasing the stiffness of the medium
c. decreasing the transducer frequency
d. increasing the density of the medium
13. For short pulses, the quality (Q) factor is equal to:
a. the distance of one pulse
b. one half of the frequency
c. the number of cycles in a pulse
d. the intensity of the sound beam
14. The positive half of a pressure wave corresponds to: