Imaging With Sound

Question 1

Area where the molecules are moved closer together longitudinal wave

Answer 1

compressions

Question 2

Rarefactions

Answer 2

area where molecules are moved apart longitudinal wave

Question 3

Frequency of sound is

Answer 3

repetition rate of the original disturbances

Question 4

20hZ - 20000hZ

Answer 4

human ear sound detection

Question 5

Ultrasound frequencies are higher than

Answer 5

20kHz

Question 6

Medical imaging use frequency range

Answer 6

1-15 MHz

Question 7

speed of sound depends on material, sound travels faster in more

Answer 7

solid material

Question 8

csound=√B/P

Answer 8

B is the bulk modulus
and ρ is the density

Question 9

Attenuation of sound

Answer 9

sound intensity increases as it travels through a medium, energy is absorbed and sound is scattered

Question 10

the further the sound travels the more it is

Answer 10

attenuated

Question 11

less attenuation in

Answer 11

denser material - air is a poor transmitter of sound

Question 12

higher frequency is more or less attenuation

Answer 12

more (opposite of x-rays)

Question 13

acoustic impedance (Z)

Answer 13

density (ρ) x speed of sound (v) units kgm-2 s
Z=pcsound

Question 14

High frequency ultrasound

Answer 14

better for fine focus and good resolution but
cannot penetrate far

Question 15

Low frequency ultrasound

Answer 15

more penetrating but cannot resolve fine
detail

Question 16

B-scan

Answer 16

• many ultrasound beams pointing in many directions.
• each beam records the position of an interface and shows this as a bright spot on a monitor screen