Chapter 9

Question 1

T or F Narrow beams create better images

Answer 1

true

Question 2

T or F As sound travels the width of beam changes

Answer 2

True

Question 3

The location where the beam reaches its minimum diameter

Answer 3

Focus or Facal point

Question 4

Distance from the transducer to focus

Answer 4

Focal depth

Question 5

Area between focus and transducer

Answer 5

Near zone

Question 6

Another name for near zone

Answer 6

Fresnel zone

Question 7

Area after focus, beyond the near zone

Answer 7

Far zone

Question 8

Another name for far zone

Answer 8

Fraunhofer zone

Question 9

The focus is located at the end of what

Answer 9

Near zone

Question 10

Starts at the focus and extends deeper

Answer 10

Far zone

Question 11

At the end of the near zone and beginning of the far zone the width of the beam is

Answer 11

One half as wide as at the transducer

Question 12

Best quality image at this depth

Answer 12

Focal zone

Question 13

Distance from the transducer to the focal point.

Answer 13

Focal depth, focal length, near zone length

Question 14

What determines the depth

Answer 14

Transducer diameter
Frequency of ultrasound

Question 15

Transducer diameter and focal depth are

Answer 15

directly related

Question 16

Larger diameter crystal

Answer 16

deeper focus

Question 17

Higher frequency and focal depth

Answer 17

directly related, deeper focus

Question 18

Sound beam divergence
Larger diameter crystal, higher frequency sound produces

Answer 18

less diverge in far field

Question 19

Sound beam divergence
smaller diameter crystal, lower frequency sound produces

Answer 19

diverge more in far field

Question 20

The principle explains the hourglass shape of an imaging transducer’s sound beam

Answer 20

Huygens’s principle