Frage 1
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Which substances have both intrinsic, and extrinsic electric conductivity:
Antworten
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Conductors
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Dielectrics (insulators)
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Semiconductors
Frage 2
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Dielectrics can be described as having:
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Free electron states in the valence band
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Wide (forbidden) band gap, and completely occupied valence band
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Extrinsic atoms from elements with different valance
Frage 3
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P-doping of semiconducting germanium (Ge), will create additional energy levels;
Antworten
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Near the conduction band of Ge
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At the forbidden band-gap of Ge
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Near the valence band of Ge
Frage 4
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The band-gap width of a dielectric (insulator) is:
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Narrower than 1 eV
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Wider than 3 eV
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Narrower than 0.01 eV
Frage 5
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Band theory of solids defines conductors as having:
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An unoccupied (free) electrons states in the valence band
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A narrow band-gap, and absence of free states in the valence band
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impurities from elements with lower valence
Frage 6
Frage
N-doping of semiconducting germanium (Ge), will create additional energy levels:
Antworten
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Near the valence band of Ge
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At the forbidden bang-gap of Ge
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Near the conduction band of Ge
Frage 7
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Valence and conductivity bans overlap partially in:
Antworten
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Metals
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Dielectrics
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Semiconductors
Frage 8
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Charge carriers of certain type (n or p) will dominate in a semiconductor when:
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The number of unoccupied electron states in valence and conduction bands are equal
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The band-gap is large, and the valence band is completely occupied
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Impurities with lower or higher valence are present
Frage 9
Frage
What is the difference between dielectrics and semiconductors, according to band theory of solids.
Antworten
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The number of electrons in valence band
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Band-gap is greater or less than 3 eV in width
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The number of occupied electron in conduction band
Frage 10
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Current carriers in semiconductors are:
Antworten
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Holes only:
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Electron and Holes
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Electrons only
Frage 11
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What type of current carriers are the holes:
Frage 12
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How does intrinsic conductivity of semiconductors depend on temperature?
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It increases with Temperature
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It decreases with Temperature
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It does not depends on Temperature
Frage 13
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How does intrinsic conductivity of semiconductors depend on Temperature?
Antworten
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A narrower band-gap results in higher conductivity.
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A narrower band-gap results in lower conductivity.
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It does not depend on the width of the band-gap.
Frage 14
Frage
What are the current carriers in a P-N junction, upon application of forward bias?
Antworten
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Electrons and Holes
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Only Electrons
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Only Holes
Frage 15
Frage
Using OHM's LAW: In order to assess the medicinal effect of a substance, in dermatology, the skin impedance Z is studied by:
Frage 16
Frage
The electric impedance of biological tissues is composed of:
Antworten
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R and Xc
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XL and Xc
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R and XL
Frage 17
Frage
Using OHM's LAW: Capacity reactance of an AC circuit is equal to:
Frage 18
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Using OHM's LAW: The direction of electrical current fluctuates with time in:
Frage 19
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Using OHM's LAW: Ohm's law states:
Frage 20
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Using OHM's LAW: Electric current is:
Frage 21
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The unit for electrical conductivity is:
Frage 22
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The unit for electrical resistance is:
Frage 23
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What type of tissue or body fluid have the highest electrical conductivity:
Antworten
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Cerebrospinal fluid
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Blood Plasma
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Blood
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Skin and Bones
Frage 24
Frage
What is the frequency of direct currents (DC)
Antworten
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50 MHz
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50 Hz
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DC has no frequency
Frage 25
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What type of electrical current is a lightning bolt?
Antworten
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Direct current (DC)
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High Frequency AC
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Low Frequency AC
Frage 26
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What type of electrical current is a galvanic current?
Antworten
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High Frequency AC
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Low Frequency AC
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Low Direct Current
Frage 27
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What type of electric impedance is present in the human tissue?
Antworten
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Inductive and Capacitive
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Resistive and Capacitive
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Resistive and Inductive
Frage 28
Frage
What type of electric impedance is present in the human tissue?
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Direct Current Only
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Alternating Current Only
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Both, AC and DC can propagate
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Neither, only electromagnetic waves can propagate.
Frage 29
Frage
Transducer is a device for:
Antworten
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Generation of metastable radionuclides
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Transformation of energy from one form to another
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Other name of linear scanner
Frage 30
Frage
What type of transducer is the piezoelectric crystal? (e.g. transducers in echo-graphs)
Frage 31
Frage
What type of transducer is the ionization chamber:
Frage 32
Frage
Which of the objects mentioned below is a transducer:
Antworten
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Permanent magnet of MRI
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Roentgen film
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Geiger-Muller Counter
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Mercury Thermometer
Frage 33
Frage
Which of the objects mentioned below is NOT a transducer:
Frage 34
Frage
Which of the following functions are performed by a photocell:
Antworten
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It converts chemical energy into electrical energy
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It converts magnetic energy into electrical energy
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It converts light energy into electrical energy
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It converts electrical energy into light energy.
Frage 35
Frage
Thermocouple is an arrangement of two different metals:
Antworten
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To convert heat into electric energy
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To convert heat into chemical energy
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To convert electrical energy into heat
Frage 36
Frage
Which of the following is NOT a transducer
Frage 37
Frage
Which is the most relevant electromyography parameter for determination of damaged tissue
Frage 38
Frage
In an active electro-diagnostics the source of E.M.F (Electromotive Force):
Antworten
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The body of the examined patient
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The electrocardiograph
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The stimulation apparatus
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The electroencephalograph
Frage 39
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In a passive electro-diagnostics the course of Electromotive Force is:
Antworten
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The body of the examined patient
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The Electrocardiograph
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The Stimulation apparatus
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The Electroencephalograph
Frage 40
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ECG is a method of:
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Examination of muscles
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Examination of the brain
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Examination of the heart
Frage 41
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EEG is a method of:
Antworten
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Examination of muscles
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Examination of the brain
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Examination of the heart
Frage 42
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EMG is a method of:
Frage 43
Frage
The active electro-diagnostic differs from the passive one in the fact that source of Electromotive Force:
Frage 44
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The defibrillator is used to:
Antworten
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Replace the heart in operations of the heart
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Restore the rhythmical contraction and relaxation of the different structures of the heart muscle (the myocard)
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Support the cardiac output
Frage 45
Frage
The cardio-stimulator (the pacemaker) is:
Antworten
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Self-recording device for measurement of the pulse and blood pressure
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Substitute of the heart in operations of the heart
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Generator of electric impulses needed for the cardiac output.
Frage 46
Frage
The cardio-stimulator (the pacemaker) is supplied by:
Frage 47
Frage
For electrostimulation on an object to occur, a minimum threshold stimulus is needed. This electrical stimulus depends on:
Frage 48
Frage
Faradization is a method for:
Antworten
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Electro-gymnastics using low frequency pulsed current
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Therapy using high frequency electric current
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Deep electro-stimulation with two interfering currents, with frequencies 2 - 5 kHz
Frage 49
Frage
Microwave therapy uses:
Antworten
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Electric field generated by an electric current with a frequency of 50 hZ
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Magnetic field generated by a direct electric current
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High frequency electromagnetic waves
Frage 50
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The most suitable frequency magnetic field is used in:
Frage 51
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High Frequency magnetic field is used in:
Antworten
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Capacitive Diathermy
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MRI Tomography
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Inductive Diathermy
Frage 52
Frage
Deep heating of tissues (Therapeutic Diathermia) is applied using a high frequency current of the order of:
Antworten
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0.3 - 5 Hz
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0.3 - 5 kHz
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0.3 - 5 MHz
Frage 53
Frage
High frequency AC is less harmful to the body than low frequency AC. This is because high frequency AC:
Frage 54
Frage
Microwave diathermy uses frequency of 2.450 GHz. This frequency is:
Antworten
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Higher than microwave oven frequency
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Lower than microwave oven frequency
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The same as microwave oven frequency
Frage 55
Frage
What type of accident is most common during microwave diathermy:
Frage 56
Frage
The most prominent effect of DC on the human body is:
Antworten
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Constant orientation of ions (polarization), followed by accommodation
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Continuous change of polarity and lack of accommodation
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Vibration of ions around equilibrium position, rotation of electrical dipoles
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Propagation through skin with irritation.
Frage 57
Frage
Which of the following effects is NOT characteristic for AC
Antworten
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Constant orientation of ions (polarization), followed by accommodation
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Continuous change of polarity and lack of accommodation
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Vibration of ions around equilibrium position, rotation of electrical dipoles
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Propagation through the skin without irritation
Frage 58
Frage
Which of the following effects is characteristic for low frequency (50 Hz) alternative current:
Antworten
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Constant orientation ions (polarization), followed by accommodation.
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Ions vibrate around equilibrium position, electrical dipoles rotate
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Passes through the skin with irritation and causes deep heating
Frage 59
Frage
Which of the following effects is characteristic of high frequency (2 MHz) alternative current:
Antworten
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Constant orientation ions (polarization), followed by accommodation.
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Ions vibrate around equilibrium position, electrical dipoles rotate
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Passes through the skin without irritation and causes deep heating.
Frage 60
Frage
Which therapeutic method causes deep tissue heating:
Frage 61
Frage
UHF with high frequency electromagnetic waves (= GHz) are used in:
Antworten
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Faradizations
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Diathermia
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Microwave Therapy
Frage 62
Frage
Negative, light aeroions have:
Antworten
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A favorable effect on humans
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A negative biological effect on humans
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A favorable effect if they are attached to dust particles.
Frage 63
Frage
Positive Aeroions have:
Antworten
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A favorable effect on humans
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A negative biological effect on humans
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A favorable effect if they are attached to dust particles
Frage 64
Frage
The franklinization (electric shower) is a method in:
Antworten
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Thermal therapy using infared rays
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Patient preparation for diagnostic imaging
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Artificial aeroionotherapy
Frage 65
Frage
In the Franklilization (electric shower) the negative electrode is:
Frage 66
Frage
Favorable effect on the organism have:
Antworten
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Light positive aeroions
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Light negative aeroions
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None of the aeroions
Frage 67
Frage
The concentration of light, negative aeroions is higher in:
Antworten
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In the forest
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Small village
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Industrial Town
Frage 68
Frage
Iontophoresis uses:
Frage 69
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Iontophoresis is a method for:
Frage 70
Frage
During Iontophoresis, if active pharmaceutical ion is positive, the active electrode is:
Antworten
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The anode (positive)
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The Cathode (negative)
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Either anode with work
Frage 71
Frage
What is the difference between Sonophoresis and Iontophoresis:
Antworten
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The former is therapeutic and the latter is diagnostic
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The external (physical) stimulus, enabling the insertion of drugs into the tissue
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The location of application.
Frage 72
Frage
The constant magnetic field applied to the patient in MRI examination is:
Antworten
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Weaker than the earths magnetic
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Much stronger than the earths magnetic field
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Equal to the Earths magnetic field.
Frage 73
Frage
What part of the hydrogen nuclei (protons) are examined tissues participates in the processes of forming a diagnostic image:
Frage 74
Frage
In order to observe the phenomenon of Nuclear Magnetic Resonance (NMR), in an atomic nucleus must be:
Frage 75
Frage
The contrast between different biological tissues in MRI is obtained from:
Antworten
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The decay of electromagnetic waves, passing through them.
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The difference in density p of tissues
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The difference in volume concentrations of hydrogen nuclei (proton)
Frage 76
Frage
Medicinal Substances with anti-oxidation properties are analysed using:
Frage 77
Frage
The chemical shift is an important parameter for direct observation of the chemical basis of disease, in:
Frage 78
Frage
Which is the most common contrast substance used in MRI
Frage 79
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Volume Concentration of Protons is a parameter in diagnostic image formation in:
Frage 80
Frage
Contrast substances used MRI are:
Antworten
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Paramagnetic
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Piezocrystals
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Photosensitive
Frage 81
Frage
Contrast substances used in MRI diagnostics modify:
Antworten
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The size of the external magnetic field
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The density of protons p in the examined tissue
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The times of relaxation T1 and T2 in the examined tissues.
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The frequency of the high frequency electromagnetic field
Frage 82
Frage
Longitudinal time of relaxation T1 is a parameter used in:
Antworten
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Positron Emission Tomography
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Echography
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Magnetic Resonance Tomography
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Roentgen Computed Tomography
Frage 83
Frage
Transversal time of relaxation T2 is parameter used in:
Frage 84
Frage
In MRI, the electric signals from different small volume elements (voxels) in examined tissues are distinguished by:
Antworten
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The applied gradient magnetic fields
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Change in the frequency of the high frequency electromagnetic field
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Introduction (injection) of contrast substance
Frage 85
Frage
The effect of the high frequency electromagnetic field on examined tissues in MRI is:
Frage 86
Frage
For which of the listed below organs and tissues, is MRI the most informative diagnostic imagine method:
Antworten
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Soft Tissues
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Bones
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Body Cavities
Frage 87
Frage
MRI coil magnets operate at very low temperature (in liquid helium) so that:
Antworten
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The risk of tissue damage is reduced
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The constant magnetic field is homogenous
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A superconductivity is achieved - Magnetizing coil wires are very thin.