Ch. 5 - Intensity

Question 1

The concentration of the power in a beam is the

Answer 1

intensity

Question 2

The equation for intensity is

Answer 2

Power
————– = Intensity (W/cm2)
Beam Area

Question 3

The units for intensity are

Answer 3

w/cm2 (watts/square cm)

Question 4

Intensity is not uniform across a _____ _____. With Pulsed U/S, intensity is not uniform throughout _____.

Answer 4

sound beam

time

Question 5

5 Key words for intensity are

Answer 5

Peak
Average
Spatial
Temporal
Pulsed

Question 6

The maximum value, when referring to Intensity, is called

Answer 6

Peak

Question 7

The mean value, when referring to Intensity, is

Answer 7

Average

Question 8

The Distance or Space, when referring to Intensity, is

Answer 8

Spatial

Question 9

The Time (all time, transmit and receive) when referring to Intensity, is

Answer 9

Temporal

Question 10

The Time that the Pulse exists (transmit only), when referring to Intensity, is

Answer 10

Pulsed

Question 11

What does SPTP stand for?

Answer 11

spatial peak
temporal peak (highest value)

Question 12

What does SATP stand for?

Answer 12

spatial average

temporal peak

Question 13

What does SPTA stand for?

Answer 13

spatial peak
temporal average (most important for thermal bioeffects)

Question 14

What does SATA stand for?

Answer 14

spatial average

temporal average

Question 15

What does SPPA stand for?

Answer 15

spatial peak

pulse average

Question 16

What does SAPA stand for?

Answer 16

spatial average

pulsed average

Question 17

All Intensities have a unit of

Answer 17

W/cm2

Question 18

T or F? An U/S beam does not have the same intensity at different locations within the beam.
(Spatial)

Answer 18

True

Question 19

T or F? An U/S does not have the same intensity at different times.
(Temporal)

Answer 19

True

Question 20

The 1st Commandment of Intensity is

Answer 20

1) Intensities may be reported in various ways with respect to time and space.

Question 21

The 2nd Commandment of Intensity is

Answer 21

2) Intensity is the key parameter with regard to bioeffects. The different Intensities are important in the study of bioeffects. SPTA Intensity is the most relevant Intensity with respect to tissue heating.

Question 22

The 3rd Commandment of Intensity is

Answer 22

3) Peak is greater than Average.

Thus, SPTP is the highest Intensity, and SATA is the lowest Intensity

Question 23

A novel way of rating numbers. The _____ of any number represents the number “10s” that are multiplied together to create the original number.

Answer 23

logarithm

Question 24

What is the log of 100?

Answer 24

10 x 10 = 100, the log of 100 is 2

Question 25

Definition: a logarithmic scale. A relative scale - ratio of the final to the initial strengths. A comparison, therefore, two intensities are needed to calculate.

Answer 25

Decibels

Question 26

What are the units of relative amplitude?

Answer 26

dB

Question 27

Positive decibels means getting _____ (smaller/bigger). The Intensity is _____ (increasing/decreasing).

Answer 27

bigger

increasing

Question 28

3dB means _____ (number) times bigger.

Answer 28

2

Question 29

10dB means _____ (number) times bigger.

Answer 29

10

Question 30

6dB means _____ x _____. Final is _____ (number) times bigger than the original.

Answer 30

2 x 2

4

Question 31

Negative Decibels means getting _____ (smaller/bigger). The Intensity is _____ (increasing/decreasing).

Answer 31

smaller

decreasing

Question 32

-3dB means _____ (number). We have fallen to _____ (fraction) of the original value.

Answer 32

one-half

half

Question 33

-10dB means _____ (number). We have fallen to _____ (fraction) of the original value.

Answer 33

one-tenth

one-tenth

Question 34

What is the meaning of -10dB? 10dB means _____ (number) times _____ (smaller/bigger). Therefore, -10dB means _____ (fraction) of the original.

Answer 34

10 times bigger

1/10

Question 35

_____ Intensity is the most relevant Intensity with respect to tissue heating.

Answer 35

SPTA