Chapter 2 - 14.3 questions

Question 1

What is the wavelength of 5 MHZ ultrasound in soft tissue ?

Answer 1

0.3 mm

Question 2

What is the wavelength of 10 MHz in bone ?

Answer 2

0.4 mm

Question 3

Given a wavelength of 1 mm and a frequency of 2MHz, what is the propagation velocity ? Do you think this medium is stiffer than soft tissue , blood bone ?

Answer 3

2000 m/sec

Question 4

Stiffness is ____________ related to compressibility , _______ related to elasticity _______- related to inelasticity

Answer 4

inversely related
inversely related
directly related

Question 5

If the transmit voltage is increased from 2 - 4 volts , the frequency will ______-

Answer 5

not change

Question 6

Frequency of ultrasound, infrasound, audible, and diagnostic ultrasound

Answer 6

infrasound 0-20 Hz
audible 20-20 kHz
ultrasound >20 kHz
diagnostic ultrasound 2 MHz - 10 MHz

Question 7

What happens to the intensity if the amplitude is increased by a factor of 3.

Answer 7

intensity increase by a factor of 9

Question 8

What happens to the intensity if the power is increased by a factor of 3 ?

Answer 8

intensity increases by a factor of 3

Question 9

What happens to the intensity if the area is increase by a factor of 2 ?

Answer 9

intensity decrease by a factor of 2

Question 10

If we keep the area fixed, and if the intensity increases by a factor of 4, what change has occurred to the amplitude?

Answer 10

Amplitude has increase by a factor of 2

Question 11

The frequency is determined strictly by the wave __________

Answer 11

source

Question 12

The period of a wave is det. strictly by the wave __________

Answer 12

source

Question 13

The propagation velocity is det. strictly by the properties of the _________.

Answer 13

medium

Question 14

The 2 two properties of the medium which determine the propagation velocity are _____________ (related to density) and _____ (related to compressibility and stiffness)

Answer 14

inertia

elasticity

Question 15

The propagation velocity ___________ with increased density (assume no change in stiffness)

Answer 15

decreases

Question 16

As the density decreases, the propagation velocity ________ (assume no change in stiffness)

Answer 16

increases

Question 17

A stiff material is not very elastic , so stiffness and elasticity are ________ related.

Answer 17

inversely

Question 18

A material which is inelastic is a stiff material and therefore has a high __________ velocity.

Answer 18

propagation

Question 19

Inelasticity and incompressibility are related to ___________

Answer 19

stiffness

Question 20

Elasticity and ________ are inversely related to stiffness

Answer 20

compressibility

Question 21

A gas is generally more compressible than a __________ which is generally more compressible than a solid.

Answer 21

a liquid

Question 22

____________ is sound below human hearing

Answer 22

infrasound

Question 23

___________ is sound above human hearing.

Answer 23

Ultrasound

Question 24

___________ ultrasound is approximately from 2MHz to 10 MHz.

Answer 24

Diagnostic

Question 25

All sound waves are _______ mechanical waves.

Answer 25

longitudinal

Question 26

Infrasound is below ________.

Answer 26

20 Hz

Question 27

Ultrasound is any sound above _________.

Answer 27

20kHz

Question 28

_____________ is the rate at which energy is transferred

Answer 28

power

Question 29

___________ is proportional to the (amplitude)^2

Answer 29

Power

Question 30

If the amplitude is doubled, the power is _______-

Answer 30

quadrupled

Question 31

If the amplitude is decreased by a factor of 2, the power is decreased by a factor of ________-

Answer 31

four

Question 32

Power is a measured in units of __________

Answer 32

watts

Question 33

The _________ is defined as the concentration of energy

Answer 33

intensity

Question 34

The fundamental units for __________ is power per area

Answer 34

intensity

Question 35

If power is given in Watts and the area is given in ________ the intensity has units of watts/cm^2

Answer 35

cm^2

Question 36

If the area is increased by a factor of 2 and the power is unchanged , the intensity is decreased by a factor of ________

Answer 36

two

Question 37

If the power increases by a factor of 2 and the area is unchanged, the intensity ___________ by a factor of________.

Answer 37

increases | 2

Question 38

If the amplitude doubles, the power ______ . If the area is not changed , the intensity is also ________-

Answer 38

quadruples | quadruples

Question 39

Intensity is proportional to the ____________ which is proportional to the ___________ squared

Answer 39

power | amplitude

Question 40

The intensity is inversely proportional to the _________.

Answer 40

area