Medical physics MCQs Part 1 ASHA
8. Match the physical (objective) with the corresponding psychophysical (subjective) properties of the sound (multiple connections are possible) a. frequency b. intensity c. acoustic spectrum A. timbre B. pitch C. loudness
a-B b-C c-A
49. What is the speed of sound in air? a. 330m/s b. 900m/s c. 1550m/s
a. 330m/s
114. Which of the following formulas relate heart rate (HR), stroke volume (SV), and cardiac output (CO)? a. CO= HR x SV b. SV= HR x CO c. HR= CO x S
a. CO= HR x SV
9. Doppler shift applies to: a. all wave phenomena b. ultrasound c. infrared EM waves
a. all wave phenomena
34. What type of membrane is commonly used for haemodialysis? a. artificial semipermeable membrane b. organic semipermeable membrane c. impermeable membrane
a. artificial semipermeable membrane
110. The volumetric flow rate Q=dV/dt of blood in the cardiovascular system is: a. constant at any given time b. greater in the pulmonary circuit c. variable: it decreases from arteries to capillaries to veins
a. constant at any given time
45. Infrasound of certain frequency and intensity can: a. damage internal organs b. increase temperature of tissues c. rearrange water molecules
a. damage internal organs
76. The speed of sound (in non-dispersive medium): a. depends on the properties of the propagating medium b. is always constant, independently of the medium c. decreases as sound moves away from its source
a. depends on the properties of the propagating medium
63. Which of the following factors has the most significant effect on the speed of propagation of sound waves? a. elastic properties of the medium b. the size of the wave front c. the pressure in gaseous environment
a. elastic properties of the medium
64. Piezoelectric effect is defined as: a. electric polarisation of solids under mechanical stress b. electro-mechanical coupling of objects falling off the tower of Pisa c. electric polarisation in a solid due to temperature gradient
a. electric polarisation of solids under mechanical stress
62. A propagating sound wave transfers: a. energy b. matter c. both energy and matter
a. energy
129. The audiogram is a method for hearing loss evaluation by measuring the threshold hearing intensity of sound for different: a. frequencies b. wavelength c. amplitudes
a. frequencies
67. Sedimentation can be used to separate particles of sizes: a. greater than 1 micrometer b. in the order of 1 nanometer c. about 1 mm
a. greater than 1 micrometer
86. Timbre is related to: a. harmonic overtunes b. wooden instruments c. falling trees
a. harmonic overtunes
103. Ideal (perfect) fluid is defined as: a. incompressible and without viscosity b. high liquidity and low density c. constant velocity and surface tension
a. incompressible and without viscosity
132. When sound wave travels from air into the human body, what happens to its speed? a. increases, because tissue has higher acoustic impedance b. decreases, because tissue has lower acoustic impedance c. it doesn't change because the speed of sound is constant
a. increases, because tissue has higher acoustic impedance
50. Cardiac resonant frequency in the range of: a. infrasound b. ultrasound c. infrared
a. infrasound
83. Ideal liquids are defined as: a. lacking internal friction b. molecular cohesive forces c. surface tension and activity
a. lacking internal friction
61. Which of the following waves are NOT mechanical? a. light b. water waves c. sound waves
a. light
98. Ultrasound waves propagate through human tissue as: a. longitudinal waves b. transverse waves c. both, longitudinal and transverse modes
a. longitudinal waves
5. Refer to the equal-loudness curve above. At frequency of 4000Hz the perceived sound is: a. louder than 1000Hz b. the same as at 1000Hz c. softer than at 1000Hz
a. louder than 1000Hz
73. Sound waves are: a. mechanical waves b. electromagnetic waves c. gravitational waves
a. mechanical waves
19. What units are used to measure blood pressure with aneroid manometer? a. mmHg, kPa b. mmHg, atm c. Nxm^-2, Torr
a. mmHg, kPa
72. Centrifuges are lab devices used to fraction biological liquids (such as plasma, CSF) into molecular constituents based on their: a. molecular mass b. electric charge c. shape
a. molecular mass
100. Why can't we hear voices (speech) when submerged under water? a. most of the sound is reflected at the air/water boundary b. sound waves do not propagate under water c. ear canals are clogged with water
a. most of the sound is reflected at the air/water boundary
134. Osmosis is: a. movement of solvent through a semipermeable membrane into a region with higher solute concentration b. movement of solute through a semipermeable membrane into a region with higher solvent concentration c. diffusion of water
a. movement of solvent through a semipermeable membrane into a region with higher solute concentration
70. The centrifugal force acts on: a. moving objects in non-inertial reference frame b. objects submerged in fluids c. objects in motion, irregardless of trajectory
a. moving objects in non-inertial reference frame
116. Most of the energy expended by the heart muscle during cardiac cycle goes into: a. overcoming the pressure in the aorta b. kinetic energy of moving blood c. heat generation
a. overcoming the pressure in the aorta
54. Exhaling is a: a. passive process during resting b. active process during resting c. related to transition of airflow from laminar to turbulent
a. passive process during resting
92. Intensity is defined as: a. power per area b. power per time c. energy per time
a. power per area
22. Pulse pressure is defined as: a. the difference between systolic and diastolic pressures b. the difference between systolic and atmospheric pressures c. the average of diastolic and systolic pressures
a. the difference between systolic and diastolic pressures
17. Doppler shift is defined as: a. the frequency difference between emitted and received signals for observers at relative motion b. the difference in acoustic impedance between two transmitting mediums c. the intensity difference between emitted and reflected waves
a. the frequency difference between emitted and received signals for observers at relative motion
39. The fundamental harmonic frequency in a complex sound is characterised by: a. the lowest frequency and highest amplitude b. the highest frequency and lowest amplitude c. the highest frequency and highest amplitude
a. the lowest frequency and highest amplitude
40. The speed of ultrasound in human tissue depends on: a. the properties of the tissue b. the properties of the apparatus c. the speed of (ultra)sound does not depend on the tissue
a. the properties of the tissue
79. If delta f is the change in frequency between emitted and received ultrasound signals due to Doppler shift during measurement of the linear speed of blood, then: a. the speed of blood relative to the stationary transducer (emitter and receiver) is greater when delta f is greater b. blood motion does not affect delta f c. the speed of blood relative to the stationary transducer is greater when delta f is smaller
a. the speed of blood relative to the stationary transducer (emitter and receiver) is greater when delta f is greater
44. Phonophoresis is: a. therapeutic application of ultrasound b. diagnostic application of ultrasound c. method for sterilisation
a. therapeutic application of ultrasound
18. At what angle to the surface of the body should the ultrasonic probe be applied in order to gain a maximum Doppler shift? Consider that Doppler shift is proportional to cos(theta). a. theta = 45 degrees b. theta = 90 degrees c. theta = 60 degrees
a. theta = 45 degrees
52. The direct piezoelectric effect is used for: a. ultrasound detectors b. ultrasound generators c. electrophoresis
a. ultrasound detectors
42. The so called "reverse piezoelectric effect" finds application in: a. ultrasound generation b. x-ray tubes c. lasers
a. ultrasound generation
117. Which of the following expressions is the formula for the propagation speed of pulse waves? a. v=k. (E.d/2rp)^1/2 b. v=k. (E.d/2rp) c. v=k. (rp/2Ed)^1/2 Where: E in the elastic modulus of vessels, d is the thickness of blood vessels, r is the radius of the lumen, and p is the blood density
a. v=k. (E.d/2rp)^1/2
15. Is it possible to tell the direction of motion of erythrocytes from the sign of the Doppler shift? a. yes when f>0 erythrocytes move towards the transducer b. yes when f>0 erythrocytes move away from the transducer c. no, the sign of delta f does no tell the direction of motion
a. yes when f>0 erythrocytes move towards the transducer
29. Does the speed of dialysis depend on the conductance of the membrane? a. yes, high conductance relates to faster dialysis b. yes, high conductance relates to slow dialysis c. there is no correlation between membrane conductance and the rate of dialysis
a. yes, high conductance relates to faster dialysis
123. Is power efficiency of the heart muscle affected by the type of blood flow in the vascular system (turbulent or laminar)? a. yes, the efficiency is greater for laminar flow b. efficiency is not effected c. yes, turbulent flow leads to better efficiency
a. yes, the efficiency is greater for laminar flow
124. For laminar blood flow the relationship between the change in blood pressure (ΔP) and the change in volumetric flow rate (ΔQ) is as follows: a. ΔQ is proportional to ΔP b. ΔQ is proportional to ΔP/3 c. ΔQ is proportional to (ΔP)^2
a. ΔQ is proportional to ΔP
4. Sound intensity (dB) and loudness (phones) will have the same magnitude at the following frequency (see equal-loudness graph) a. 20Hz b. 1000Hz c. 20kHz
b. 1000Hz
128. The speed of sound in the human body is approximately: a. 330 m/s b. 1500 m/s c. 6000 m/s
b. 1500 m/s
126. The human ear is sensitive to frequencies in the range: a. 20 Hz- 20 MHz b. 200 Hz- 20 kHz c. 20 Hz- 2000 Hz
b. 200 Hz- 20 kHz c. 20 Hz- 2000 Hz
16. If shorter wavelengths of ultrasound are less penetrating in human tissue, then which of the following frequencies is most appropriate for DEEP tissue and organ imaging? a. 8MHz b. 3MHz c. 20MHz
b. 3MHz
113. Which of the following formulas relates volumetric flow rate Q to linear speed v and surface area S of a fluid in a closed circuit (blood)? a. V= QS b. Q= vS c. S= Qv
b. Q= vS
96. Mechanical waves used for destruction of kidney stones, in procedure called "lithotripsy", cause minimal damage to surrounding tissues because: a. mechanical waves do not propagate through the surrounding tissue b. acoustic pressure in the surrounding tissue is greatly reduced compared to the pressure induced in the kidney stones c. mechanical waves do not have negative effect on soft tissue
b. acoustic pressure in the surrounding tissue is greatly reduced compared to the pressure induced in the kidney stones
24. When blood pressure is measured with a stethoscope, at what point is the systolic pressure detected? a. at the loudest sound b. at the first sound c. when the sound disappears
b. at the first sound
102. Laplace pressure ΔP does not depend on: a. the radius of the surface b. atmospheric pressure c. the coefficient of surface tension σ
b. atmospheric pressure
71. What are the respective directions of centrifugal and centripetal forces acting on an object on a circular trajectory? a. centrifugal force points inward (towards axis of rotation) and centripetal force and points outwards b. centripetal forces points inwards, and centrifugal force points outward c. both forces point outwards
b. centripetal forces points inwards, and centrifugal force points outward
41. The speed of sound is calculated by the Newton-Laplace formula where K is the stiffness coefficient and p is the density of the material. If the density of the substance doubles, the speed of propagating sound wave will: a. increase b. decrease c. depends on the frequency
b. decrease
3. The loss of elasticity (stiffening) of the tympanic membrane will result in: a. increase of air conductivity b. decrease of hearing threshold c. decrease in binaural effect
b. decrease of hearing threshold
121. Reynolds number (Re) is unitless quantity used to: a. determine types of mechanical wave phenomena: infrasound or ultrasound b. determine the type of fluid flow: laminar or turbulent c. determine the type of x-rays: soft or hard
b. determine the type of fluid flow: laminar or turbulent
122. During turbulent motion, particles move: a. parallel and unidirectional, in coaxial cylindrical layers. Where each layer has a constant speed, which increases away from the vessel walls and toward the central axis b. disorderly c. parallel and unidirectional, in coaxial cylindrical layers. Where each layer has a constant speed, which increases away from the centre axis and toward the vessel walls
b. disorderly
10. The contact gel used in ultrasonography (echography) is for: a. protection of the body from harmful ultrasound b. efficient transmission of sound waves into the tissue c. improvement of skin elasticity in the area of study
b. efficient transmission of sound waves into the tissue
69. Which of the following forces is not relevant during erythrocyte sedimentation for determination of ESR (erythrocyte sedimentation rate)? a. gravity b. electrostatic forces c. Archimedes force
b. electrostatic forces
77. The human ear is most sensitive to frequencies (refer to the equal-loudness curve): a. below 1000Hz b. from 2000Hz to 5000Hz c. above 5000Hz
b. from 2000Hz to 5000Hz
84. What quantity is transferred when there is internal friction? a. mass b. impulse c. charge
b. impulse
119. The pulse wave propagates , and is detectible in: a. the entire cardiovascular system b. in the arteries c. in the capillaries
b. in the arteries
109. Where in the cardiovascular system is the blood pressure at minimum? a. in the capillaries b. in the veins c. in the aorta
b. in the veins
133. Speed of pulse waves in atherosclerotic vessels is: a. decreased (slower) b. increased (faster) c. unaffected
b. increased (faster)
101. The resonant frequency of the internal organs is in the range of: a. 10 MHz b. infrasound c. ultrasound
b. infrasound
51. The resonant frequency of the vestibular system is in the range of: a. ultrasound b. infrasound c. ultraviolet
b. infrasound
48. Choose the correct range: a. audible sound: 103Hz-106Hz b. infrasound: 3Hz-10Hz c. ultrasound: 10kHz-100kHz
b. infrasound: 3Hz-10Hz
104. What property of sound is measured in decibels (dB)? a. wavelength b. intensity level c. loudness
b. intensity level
55. Does the absorption of sound and the corresponding penetration depth depend on the wavelength? a. no b. it does, there is less absorption at longer wavelengths and they propagate deeper c. it does, there is less absorption at shorter wavelengths and they propagate deeper
b. it does, there is less absorption at longer wavelengths and they propagate deeper
20. What is the predominant type of blood flow in the arteries of a health person? a. turbulent b. laminar c. transitional
b. laminar
43. Ultrasound can propagate through: a. vacuum b. matter c. everywhere where light propagates
b. matter
94. When sound wave travels across two materials with similar acoustic impedance, at the boundary surface there will be: a. similar amounts of transmission and reflection b. more transmission and less reflection c. less transmission and more reflection
b. more transmission and less reflection
11. In medical imaging, Doppler echography is most appropriate for: a. deep body targets b. moving body targets c. surface targets
b. moving body targets
37. During haemodialysis, is it necessary for the dialysate solution to be hypertonic? a. yes, because this way ions will flow back into the blood b. not necessary, because it could have negative effects on the dialysis c. it is necessary, in order not to slow down dialysis
b. not necessary, because it could have negative effects on the dialysis
35. In the dialysis column, blood and dialysate travel in: a. the same direction b. opposite directions c. blood travels while the dialysate stays still
b. opposite directions
58. Damping oscillations are: a. oscillations with increasing amplitude b. oscillations with decreasing amplitude c. not related to amplitude
b. oscillations with decreasing amplitude
127. What are the SI units for loudness? a. sone b. phon c. dB
b. phon
38. Sound frequency is: a. psychophysical property (subjective) b. physical property (objective) c. sound is measured in wavelength, and light is measured in frequency
b. physical property (objective)
80. Timbre is: a. physical (objective) property of sound b. psychophysical (subjective) sound property c. type of wood found in North America
b. psychophysical (subjective) sound property
28. Haemodialysis is a method for: a. determination of serum proteins by blood dialysis b. removing toxins from patient's blood c. investigating brain haemodialysis
b. removing toxins from patient's blood
88. Which natural science studies infrasound? a. pediatrics b. seismology c. dental medicine
b. seismology
135. Which of the following is absolutely necessary for the process of osmosis to occur? a. water b. semipermeable membrane c. sodium ions
b. semipermeable membrane
1. Sound amplification in the outer ear (auditory canal) is affected by: a. sound speed b. sound pressure c. sound amplitude
b. sound pressure
87. Which of the following does not have relevance to the reflection/transmission of sound waves? a. the acoustic impedance of substances at the boundary b. the colours of substances near the boundary area c. the cross sectional area of the boundary surface
b. the colours of substances near the boundary area
97. The acoustic impedance Z of a substance is defined as the product of: a. the density and the atomic number of the element: pZ b. the density and the speed of sound: pv c. the temperature and the speed of sound: v
b. the density and the speed of sound: pv
82. The speed of arterial pulse wave depends mostly on: a. the haematocrit b. the elasticity of blood vessels c. the cross section of blood vessels
b. the elasticity of blood vessels
23. What is the most precise definition of blood pressure? a. the pressure in the cardio-vascular system b. the pressure exerted by blood on the walls of blood vessels c. the pressure in the arteries
b. the pressure exerted by blood on the walls of blood vessels
108. When sound wave propagates between two media with similar impedance, there will be: a. equal amounts of transmission and reflection b. there will be more transmission and less reflection c. there will be more reflection and less transmission
b. there will be more transmission and less reflection
53. What causes the Korotkoff sounds? a. high blood pressure b. turbulent flow of blood around constrictions c. high pulse rate
b. turbulent flow of blood around constrictions
74. Mechanical waves with frequency above 20kHz are called: a. infrasound b. ultrasound c. P-waves
b. ultrasound
93. A necessary condition for internal friction (viscous force) in fluid dynamics is: a. concentration gradient b. velocity gradient c. electric charge gradient (potential difference)
b. velocity gradient
115. Does heart rate change with aging? a. yes, increases b. yes, decreases c. does not change
b. yes, decreases
56. Is it possible for internal organs to generate sounds that propagate to the skin and are audible? a. no b. yes, organs produce sounds that propagate through the tissues and are audible at the skin c. no, organs generate sounds but the waves are absorbed by the tissues are inaudible at the skin
b. yes, organs produce sounds that propagate through the tissues and are audible at the skin
125. For turbulent blood flow the relationship between the change in blood pressure (ΔP) and the change in volumetric flow rate (ΔQ) is as follows: a. ΔQ is proportional to ΔP b. ΔQ is proportional to (ΔP)^2 c. ΔQ is proportional to ΔP/5
b. ΔQ is proportional to (ΔP)^2
36. During haemodialysis, why is it important to keep blood pressure higher than dialysate pressure? a. to force toxic substances from the blood into the dialysate b. to prevent backflow of substances from dialysate solution into the blood c. to facilitate ultrafiltration (remove excess water out of the blood stream)
b/c b. to prevent backflow of substances from dialysate solution into the blood c. to facilitate ultrafiltration (remove excess water out of the blood stream)
14. For which of the following numerical Doppler frequency shifts is the blood speed the highest? a. 1210Hz b. 800Hz c. 1530Hz
c. 1530Hz
32. Toxin concentrations in blood during haemodialysis can be modelled with an exponential decay law. Using the graph (see book), estimate the time it takes for toxin conc to decrease from 60 to 40% of the original. a. 5h b. 2.5 min c. 2.5h
c. 2.5h
105. If the period of a wave is 0.02s, what is its frequency? (Hint: how often does it vibrate in one second?) a. 200 Hz b. 100 Hz c. 50 Hz
c. 50 Hz
7. The sound intensity level in a room is 20dB. A TV produces additional intensity level of 60dB. What is the sound intensity in the room now? a. 80dB b. 40dB c. 60dB
c. 60dB
21. Blood pressure on the walls of blood vessels is compensated (counterbalanced) by the elasticity of blood vessels, and by the air pressure. If the reading of the sphygmomanometer during a systole is 120mmHg and air pressure is 760mmHg, what is the actual pressure that blood exerts on the walls of arteries? a. 90mmHg b. 640mmHg c. 880mmHg
c. 880mmHg
89. Which of the following parameters is the most informative for the blood supply of a given organ? a. arterial pressure b. the speed of blood c. blood flow
c. blood flow
12. In what form is the information received with Doppler echography displayed: a. by sound b. by one dimensional image c. by two dimensional image with artificial colouring
c. by two dimensional image with artificial colouring
90. A necessary condition for diffusion is: a. semipermeable membrane b. temperature gradient c. concentration gradient
c. concentration gradient
130. Pure tone is characterised by: a. deviation from the equilibrium is proportional to the frequency b. constant velocity vector c. constant frequency
c. constant frequency
107. Which of the following properties of sound is measured in Hertz (Hz)? a. power b. amplitude c. frequency
c. frequency
120. In the cardiovascular system (CVS) of healthy young person, turbulent flow is found: a. in the entire CVS b. in the capillaries c. in the Aortic arch
c. in the Aortic arch
6. Sound intensity level is proportional to the logarithm of the ratio of incoming to threshold intensity SIL= 10xlog (I/Io). If the intensity is increased by the factor of 100, what is the change in SIL? a. increase by a factor of 10 (10 times) b. double (2 times) c. increase with 20dB (plus 20dB)
c. increase with 20dB (plus 20dB)
2. Prolonged experience to loud noise can cause permanent damage to: a. the air conductivity of the ear b. the structure of the eardrum c. inner ear
c. inner ear
26. What is the variation of blood pressure across the cardio-vascular system: a. it decrease linearly from arteries to veins b. it oscillates between diastolic and systolic but stays mostly the same c. it decreases non-linearly with the greatest drop at the capillaries
c. it decreases non-linearly with the greatest drop at the capillaries
31. Gas embolism of blood vseels (blockage) can be explained by the: a. reynolds number Re b. blood viscosity c. laplace pressure
c. laplace pressure
81. Gas embolism (clogging of blood vessel) can be explained with: a. reynolds number (Re) b. dynamic viscosity of blood c. laplace pressure
c. laplace pressure
95. The concentration of light negative ions in the air is least in: a. in the mountains b. in the countryside c. large industrial cities
c. large industrial cities
75. Infrasound is: a. electromagnetic waves with frequency under 20Hz b. mechanical waves with frequency above 20Hz c. none of the above
c. none of the above
131. Which of the following is used in Doppler echography? a. magnetic resonance b. vacuum tubes c. piezoelectric effect
c. piezoelectric effect
118. How does the linear speed of blood compare to the speed of a pulse wave? a. they are identical b. blood moves faster than the pulse wave c. pulse wave moves faster than blood
c. pulse wave moves faster than blood
112. Which of the following parameters of the vascular system have the greatest effect on blood flow resistance? a. viscosity of blood b. volumetric flow rate c. radius of vessels lumen
c. radius of vessels lumen
85. The pitch of sound depends mostly on: a. intensity of sound b. sound pressure c. sound frequency
c. sound frequency
47. Choose the correct statement: a. ultrasound is completely harmless for humans and animals b. sound reflection depends on the transparency of the medium c. sound impedance does not depend on the frequency (for linear mediums)
c. sound impedance does not depend on the frequency (for linear mediums)
57. Noise can be defined as: a. intense sound with constant frequency b. directed sound waves with low intensity and changing modulation c. superposition of random sound vibrations, with frequency and amplitude constantly changing in time
c. superposition of random sound vibrations, with frequency and amplitude constantly changing in time
13. Doppler frequency (shift) is: a. the infrared spectrum of light, studied by Doppler b. the frequency generated by ultrasonic transducer c. the difference between emitted and reflected (received) frequency between two objects in relative motion
c. the difference between emitted and reflected (received) frequency between two objects in relative motion
91. Weber-Fechner law (in psychophysics) describes a logarithmic relationship between the intensity of a sound wave and....: a. acoustic pressure b. the sound pitch c. the perception of loudness
c. the perception of loudness
78. What is the meaning of 0dB? a. there is no sound b. the sound is below hearing threshold level c. the sound is at threshold reference level
c. the sound is at threshold reference level
66. Which statement is correct? a. the size of the ultrasonic equipment (echograph) influences the acoustic density of imaged tissue b. the precision of the ultrasonic instrument does not have the effect on the quality of received images c. the ultrasonic image, displayed on the monitor, represents the acoustic density of studied tissues
c. the ultrasonic image, displayed on the monitor, represents the acoustic density of studied tissues
33. During haemodialysis , the proper concentration of electrolytes in the dialysate is evaluated continuously by measuring the conductivity of the solution. If conductivity decreases that means: a. there are more electrolytes b. there are air bubbles c. there are less electrolytes
c. there are less electrolytes
59. If the amplitude of a wave double, what happens to the period? a. it will double b. it will be halved c. there will be no change
c. there will be no change
68. Why is sedimentation not a practical separation technique for particles smaller than 1 micron? a. cohesive forever pull particles back to the surface b. the large cross-section of particles prevents sedimentation c. thermal chaotic motion dominates over gravitational forces
c. thermal chaotic motion dominates over gravitational forces
99. Can humans sense infrasound waves? a. only when the intensity of the wave is sufficiently high for the ear to detect b. no, that's why they are called infra-sound c. they can be sensed as vibrations by the tactile receptors of the skin
c. they can be sensed as vibrations by the tactile receptors of the skin
30. What is the purpose of the air micro-bubble detector in the haemodialysis machine? a. to check the oxygen level in the blood b. to check the levels of carbon dioxide in the blood c. to prevent gas (air) embolism
c. to prevent gas (air) embolism
27. What property of blood is characterised by the Reynolds number? a. blood viscosity b. blood speed c. type of blood flow - laminar or turbulent
c. type of blood flow - laminar or turbulent
46. Infrasound cannot propagate through: a. soft tissue b. bones c. vacuum
c. vacuum
60. In which of the following mediums, can sound waves not propagate? a. gases b. liquids c. vacuum
c. vacuum
111. Linear velocity of blood in the cardiovascular system is: a. constant at any given time b. variable: decreases from arteries to capillaries to veins c. variable: lowest in the capillaries
c. variable: lowest in the capillaries
25. When blood pressure is measured is measured with a stethoscope, at what point is the diastolic pressure detected? a. at loudest sound b. at the first sound c. when sounds disappear
c. when sounds disappear
65. Does human tissue exhibit piezoelectric properties? a. no, the human body exhibits only capacitive properties b. no, piezoelectric properties are observed in inorganic crystals c. yes, tissue (type of collagen) has piezoelectric properties
c. yes, tissue (type of collagen) has piezoelectric properties