Flashcards in Lesson 8 (Part 1) Deck (30)

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1

## What is the opposite of reflection?

### Transmission

2

## Reflection

### The throwing back by a body or surface of light, heat or sound without absorbing it

3

## What happens at each point boundary with perpendicular incidence? (2)

###
1. Some of the sound is reflected

2. Some of the sound beam goes through

4

## What is another word for perpendicular incidence?

### 90 degree incidence

5

## IRC

### Intensity reflection coefficient

6

## Intensity reflection coefficient

### Is the ratio of the intensity of the reflected wave relative to the incident (transmitted) wave

7

## Incident pulse

### Is a pulse where the incident moves towards (i.e., approaching) the boundary with the pole

8

## Reflected pulse

###
A pulse with an upward displacement will reflect off the end and return with a downward displacement

- an echo

9

## Transmitted pulse

### The amplitude is representative of the energy carried by a wave

10

## What is the equation for IRC?

### IRC = echo intensity/incident sound intensity x 100%

11

## ITC

### Intensity transmission coefficient

12

## Intensity transmission coefficient

###
Is a measure of how much of an electromagnetic wave (light) passes through a surface or an optical element

- can be measured for amplitude or intensity

13

## What is the formula for ITC?

### ITC = transmitted intensity/ incident sound intensity x 100%

14

## What is the relationship between impedance and density / propagation speed?

###
Directly proportional

15

## Where is impedance the highest?

###
In solid structures

- eg. bone

16

## Where is impedance the lowest?

### In air

17

## What does impedance depend on?

### Densities

18

## What does it mean when you have a higher difference in impedance?

### A brighter echo

19

## What does IRC + ITC equal?

### 100%

20

## What is the % of transmitted pulses?

### 80%

21

## What is the % of reflected pulses?

### 20%

22

## How much goes through and how much is reflected depends on what?

### Impedance

23

## What is the formula for impedance?

###
z = p x c

z = impedance

p = density

c = propagation speed

24

## What is the unit for impedance?

###
Rayls

- kg x m / m^3 x s

25

## Does each tissue have its own impedance?

### Yes

26

## What is the formula for acoustic impedance mismatch?

### delta z = z2 - z1

27

## What does the amount of reflection depend on?

### delta z

28

## What is the formula for IRC? (involving impedance)

### IRC = (z2-z1 / z2+z1)^2

29

## What does delta z decide?

### If the echo will appear bright or dark

30