day 2

Question 1

similar to the ordinary sounds we hear except that its frequency is higher than the range of human hearing

Answer 1

ultrasound

Question 2

traveling variation in one or more quantities, such as pressure

Answer 2

wave

Question 3

concentration of matter (mass per unit volume).

Answer 3

density

Question 4

acoustic variables

Answer 4

period
wavelenght
amplitude
frequency
velocity

Question 5

Regions of low pressure and density are called

Answer 5

rarefactions

Question 6

regions of high pressure and density are called

Answer 6

compression

Question 7

Sound is a mechanical compressional wave in which back-andforth particle motion is parallel to the direction of wave. Such a wave is called

Answer 7

longitudinal wave

Question 8

The up-and-down motion of a water surface is perpendicular
to the direction of wave travel. This type of wave is called

Answer 8

transverse wave

Question 9

time that it takes for one cycle to
occur

Answer 9

period

Question 10

length of space that one cycle takes up. It is the length of a cycle from “front” to “back.”

Answer 10

wavelength

Question 11

measurement of how often something happens

Answer 11

frequency

Question 12

one complete variation in pressure or other acoustic variable

Answer 12

cycle

Question 13

number of times it is
repeated in 1 second is
called

Answer 13

frequency

Question 14

number of cycles in a wave that occur in 1 second.

Answer 14

frequency

Question 15

sound of a frequency too low for human hearing. less than 20 Hz

Answer 15

infrasound

Question 16

sound of a frequency too high for human hearing. 20000 Hz higher

Answer 16

ultrasound

Question 17

It is determined by the medium, primarily its stiffness

Answer 17

propagation speed

Question 18

resistance of a material to compression

Answer 18

stiffness

Question 19

The average propagation speed of sound in tissues

Answer 19

1.54 mm/μs

Question 20

Propagation in which speed depends on pressure and the shape of the wave changes

Answer 20

nonlinear propagation

Question 21

even and odd
multiples of fundamental
frequency

Answer 21

harmonics

Question 22

Any other wave shape contains additional frequencies that are even and odd multiples of the original frequency. The original frequency is called the

Answer 22

fundamental frequency

Question 23

even and odd multiples of fundamental frequency

Answer 23

harmonics

Question 24

The first working version of
marine SONAR (Sound Navigation
and Ranging) system was used
during the First World War to detect
enemy submarine

Answer 24

1916

Question 25

early scanning technique required the patient to immersed in a bath of water in order to provide good transmission of sound wave into the body

Answer 25

early 1950’s

Question 26

first contact compound B-Scanner (olive oil as lubricant) was developed

Answer 26

late 1950s

Question 27

gray scale imaging was introduced, enabling the display of a wide range of echo amplitudes

Answer 27

1970s

Question 28

real-time scanning systems were introduced. Dynamic Sonograhic
Information was available for
the first time

Answer 28

Mid 1970s

Question 29

Doppler Technique is used

Answer 29

1980s