CH. 15-REST FINAL EXAM QUESTIONS

Question 1

HOW DO YOU DESCRIBE THE PRP?

Answer 1

THE SUM OF THE PULSE’S ON TIME AND THE LISTENING OFF TIME

Question 2

DO ALL SOUND WAVES TRAVEL IN THE SAME MEDIUM AT IDENTICAL SPEEDS?

Answer 2

YES

Question 3

WHAT ESTABLISHES THE PRF?

Answer 3

THE SOURCE OF THE SOUND

Question 4

WHAT IS THE TYPICAL VALUE FOR THE DUTY FACTOR OF PULSED SOUND WAVES USED IN U/S?

Answer 4

0.001

Question 5

WITH PULSED U/S WHAT IS THE MAXIMUM VALUE OF THE DUTY FACTOR?

Answer 5

LESS THAN 100% (100% WOULD MEAN CONTINUOUS WAVE)

Question 6

WHAT IS THE IMPORTANCE OF DESCRIBING SOUND BEAM INTENSITIES IN A VARIETY OF WAYS WITH REGARD TO SPACE AND TIME?

Answer 6

IT’S IMPORTANT WHEN STUDYING BIOEFFECTS

Question 7

WHICH INTENSITY IS MOST CLOSELY CORRELATED TO TISSUE HEATING?

Answer 7

SPTA (REMEMBER SPCA)

Question 8

WHAT DETERMINES ATTENUATION?

Answer 8

PATH LENGTH AND FREQUENCY OF SOUND

Question 9

AN ACOUSTIC WAVE IS TRAVELING THROUGH SOFT TISSUE. ITS INTENSITY UNDERGOES 6 DECIBELS OF ATTENUATION. HOW DOES THE FINAL INTENSITY OF THE WAVE RELATE TO THE INTENSITY OF THE WAVE WHEN IT STARTED ITS JOURNEY?

Answer 9

IT IS NOW ONE-FOURTH AS LARGE (-3 DB IS ONE HALF, ANOTHER -3 WOULD BE ONE FOURTH)

Question 10

WHEN IS A BOUNDARY CONSIDERED SMOOTH FOR SPECULAR REFLECTION?

Answer 10

WHEN IRREGULARITIES IN ITS SURFACE ARE SMALLER THAN THE WAVELENGTH OF THE INCIDENT ULTRASONIC BEAM

Question 11

A SOUND WAVE REACHES A ROUGH OR IRREGULAR BORDER BETWEEN TWO MEDIA. UNDER THESE EXPLICIT CIRCUMSTANCES, WHICH PROCESS IS MOST LIKELY TO OCCUR?

Answer 11

BACKSCATTER / DIFFUSE REFLECTION (BOUNDARIES HAS IRREGULARITIES THAT ARE LARGER THAN THE WAVELENGTH OF THE INCIDENT ACOUSTIC PULSE, SO THE REFLECTIONS ARE DISPERSED IN MULTIPLE DIRECTIONS)

Question 12

WHAT IS THE UNIFORM DISPERSION OF A SOUND WAVE IN MANY DIFFERENT DIRECTIONS AFTER STRIKING A VERY SMALL PARTICLE?

Answer 12

RAYLEIGH SCATTERING (THE DIMENSION OF THE REFLECTING PARTICLE IS USUALLY LESS THAN THE WAVELENGTH OF THE U/S WAVE) EX: BLOOD CELLS

Question 13

HOW IS RAYLEIGH SCATTERING EXPRESSED?

Answer 13

FREQUENCY RAISED TO THE FOURTH POWER

Question 14

WHAT IS THE CONVERSION OF ACOUSTIC ENERGY INTO HEAT CALLED?

Answer 14

ABSORPTION

Question 15

WHAT IS THE AMOUNT OF ATTENUATION PER CM THAT A SOUND WAVE UNDERGOES CALLED?

Answer 15

ATTENUATION COEFFICIENT

Question 16

WHAT HAS LOWEST ATTENUATION OF U/S?

Answer 16

WATER

Question 17

WHAT HAS SECOND LOWEST ATTENUATION OF U/S?

Answer 17

BLOOD

Question 18

WHAT HAS THIRD LOWEST ATTENUATION OF U/S?

Answer 18

FAT

Question 19

WHAT HAS FOURTH LOWEST ATTENUATION OF U/S?

Answer 19

MUSCLE

Question 20

WHAT HAS FIFTH LOWEST ATTENUATION OF U/S?

Answer 20

BONE

Question 21

WHAT HAS HIGHEST ATTENUATION OF U/S?

Answer 21

AIR

Question 22

ARE ATTENUATION AND PROPAGATION RELATED?

Answer 22

NO

Question 23

WHAT ARE THE TWO ATTRIBUTES OF ACOUSTIC IMPEDANCE OF A MEDIUM?

Answer 23

DENSITY AND STIFFNESS

Question 24

THE ANGLE BETWEEN THE DIRECTION OF PROPAGATION AND THE BOUNDARY BETWEEN 2 MEDIA IS 90 DEGREES. WHAT TERM DESCRIBES THE FORM OF INCIDENCE OF THE WAVE?

Answer 24

ORTHOGONAL

Question 25

WHAT ARE SYNONYMS FOR ORTHOGONAL?

Answer 25

AT RIGHT ANGLES, 90 DEGREES, NORMAL, PERPENDICULAR

Question 26

A SOUND WAVE STRIKES A BOUNDARY BETWEEN 2 MEDIA AT 60 D AND IS CALLED WHAT?

Answer 26

OBLIQUE INCIDENCE

Question 27

HOW IS THE INTENSITY TRANSMISSION COEFFICIENT DEFINED?

Answer 27

THE PERCENTAGE OF AN U/S BEAM'S INTENSITY THAT IS TRANSMITTED AS THE SOUND WAVE PASSES THROUGH A BOUNDARY BETWEEN 2 MEDIA (NO UNITS USED!)

Question 28

WHAT RESULTS WHEN REFLECTED INTENSITY IS DIVIDED BY INCIDENT INTENSITY?

Answer 28

INTENSITY REFLECTION COEFFICIENT

Question 29

WHAT RESULTS WHEN THE INTENSITY TRANSMISSION COEFFICIENT AND THE INTENSITY REFLECTION COEFFICIENT ARE ADDED TOGETHER?

Answer 29

THEY EQUAL 1 OR 100%

Question 30

WHAT DOES THE LAW OF CONSERVATION OF ENERGY STATE?

Answer 30

THE SUM OF THE PERCENTAGE OF TRANSMITTED SOUND AND THE REFLECTED SOUND EQUALS 100%

Question 31

UNDER THE CONDITIONS OF ORTHOGONAL/NORMAL INCIDENCE, WHAT DOES REFLECTION DEPEND ON?

Answer 31

DIFFERENCES IN THE ACOUSTIC IMPEDANCES OF THE MEDIA ON EITHER SIDE OF THE BOUNDARY

Question 32

WHAT DO GREATER DIFFERENCES BETWEEN 2 IMPEDANCES CREATE?

Answer 32

STRONGER REFLECTIONS (SLIGHTLY DIFFERENT IMPEDANCES WILL PRODUCE WEAK REFLECTIONS)

Question 33

TRUE OR FALSE: LARGER REFLECTIONS OCCUR WITH GREATER IMPEDANCE DIFFERENCES

Answer 33

TRUE