Lesson 8 (Part 2) Flashcards Preview

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Flashcards in Lesson 8 (Part 2) Deck (13)
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1

What does delta z mean when it is equal to 0?

Total transmission
- no echoes

2

Echoes

The reflection and scattering of sound waves

3

What are 2 types of incidences?

1. Perpendicular
2. Oblique

4

Perpendicular incidence

Denotes a direction of travel of the ultrasound wave perpendicular to the boundary between 2 medias

5

Does transmitted sound change direction?

No, it continues to the second medium

6

What does intensities depend on?

Incident intensity at the boundary and the impedance of the media on either side of the boundary

7

What happens to impedance if density and propagation speed increases?

It increases

8

What happens to the IRC if the difference of impedances increase?

It increases

9

What does transmission coefficient depend on?

The reflection coefficient

10

What happens to the ITC if the IRC increases?

It decreases

11

What happens when ultrasound encounters a boundary with perpendicular incidence?

The impedances of the tissue must be different to produce a reflection

12

What 2 things must be known in order to calculate the reflected intensity?

1. 2 media impedances
2. Incident intensity

13

With perpendicular incidence, what does the reflected intensity depend on? (2)

1. The impedance difference
2. The impedance sum