Questão 1
Questão
Which substances have both intrinsic, and extrinsic electric conductivity:
Responda
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Conductors
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Dielectrics (insulators)
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Semiconductors
Questão 2
Questão
Dielectrics can be described as having:
Responda
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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
Questão 3
Questão
P-doping of semiconducting germanium (Ge), will create additional energy levels;
Responda
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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
Questão 4
Questão
The band-gap width of a dielectric (insulator) is:
Responda
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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
Questão 5
Questão
Band theory of solids defines conductors as having:
Responda
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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
Questão 6
Questão
N-doping of semiconducting germanium (Ge), will create additional energy levels:
Responda
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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
Questão 7
Questão
Valence and conductivity bans overlap partially in:
Responda
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Metals
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Dielectrics
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Semiconductors
Questão 8
Questão
Charge carriers of certain type (n or p) will dominate in a semiconductor when:
Responda
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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
Questão 9
Questão
What is the difference between dielectrics and semiconductors, according to band theory of solids.
Responda
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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
Questão 10
Questão
Current carriers in semiconductors are:
Responda
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Holes only:
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Electron and Holes
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Electrons only
Questão 11
Questão
What type of current carriers are the holes:
Questão 12
Questão
How does intrinsic conductivity of semiconductors depend on temperature?
Responda
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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
Questão 13
Questão
How does intrinsic conductivity of semiconductors depend on Temperature?
Responda
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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.
Questão 14
Questão
What are the current carriers in a P-N junction, upon application of forward bias?
Responda
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Electrons and Holes
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Only Electrons
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Only Holes
Questão 15
Questão
Using OHM's LAW: In order to assess the medicinal effect of a substance, in dermatology, the skin impedance Z is studied by:
Questão 16
Questão
The electric impedance of biological tissues is composed of:
Responda
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R and Xc
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XL and Xc
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R and XL
Questão 17
Questão
Using OHM's LAW: Capacity reactance of an AC circuit is equal to:
Questão 18
Questão
Using OHM's LAW: The direction of electrical current fluctuates with time in:
Questão 19
Questão
Using OHM's LAW: Ohm's law states:
Questão 20
Questão
Using OHM's LAW: Electric current is:
Questão 21
Questão
The unit for electrical conductivity is:
Questão 22
Questão
The unit for electrical resistance is:
Questão 23
Questão
What type of tissue or body fluid have the highest electrical conductivity:
Responda
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Cerebrospinal fluid
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Blood Plasma
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Blood
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Skin and Bones
Questão 24
Questão
What is the frequency of direct currents (DC)
Responda
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50 MHz
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50 Hz
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DC has no frequency
Questão 25
Questão
What type of electrical current is a lightning bolt?
Responda
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Direct current (DC)
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High Frequency AC
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Low Frequency AC
Questão 26
Questão
What type of electrical current is a galvanic current?
Responda
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High Frequency AC
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Low Frequency AC
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Low Direct Current
Questão 27
Questão
What type of electric impedance is present in the human tissue?
Responda
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Inductive and Capacitive
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Resistive and Capacitive
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Resistive and Inductive
Questão 28
Questão
What type of electric impedance is present in the human tissue?
Responda
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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.
Questão 29
Questão
Transducer is a device for:
Responda
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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
Questão 30
Questão
What type of transducer is the piezoelectric crystal? (e.g. transducers in echo-graphs)
Questão 31
Questão
What type of transducer is the ionization chamber:
Questão 32
Questão
Which of the objects mentioned below is a transducer:
Responda
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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
Questão 33
Questão
Which of the objects mentioned below is NOT a transducer:
Questão 34
Questão
Which of the following functions are performed by a photocell:
Responda
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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.
Questão 35
Questão
Thermocouple is an arrangement of two different metals:
Responda
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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
Questão 36
Questão
Which of the following is NOT a transducer
Questão 37
Questão
Which is the most relevant electromyography parameter for determination of damaged tissue
Questão 38
Questão
In an active electro-diagnostics the source of E.M.F (Electromotive Force):
Responda
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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
Questão 39
Questão
In a passive electro-diagnostics the course of Electromotive Force is:
Responda
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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
Questão 40
Questão
ECG is a method of:
Responda
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Examination of muscles
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Examination of the brain
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Examination of the heart
Questão 41
Questão
EEG is a method of:
Responda
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Examination of muscles
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Examination of the brain
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Examination of the heart
Questão 42
Questão
EMG is a method of:
Questão 43
Questão
The active electro-diagnostic differs from the passive one in the fact that source of Electromotive Force:
Questão 44
Questão
The defibrillator is used to:
Responda
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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
Questão 45
Questão
The cardio-stimulator (the pacemaker) is:
Responda
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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.
Questão 46
Questão
The cardio-stimulator (the pacemaker) is supplied by:
Questão 47
Questão
For electrostimulation on an object to occur, a minimum threshold stimulus is needed. This electrical stimulus depends on:
Questão 48
Questão
Faradization is a method for:
Responda
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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
Questão 49
Questão
Microwave therapy uses:
Responda
-
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
Questão 50
Questão
The most suitable frequency magnetic field is used in:
Questão 51
Questão
High Frequency magnetic field is used in:
Responda
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Capacitive Diathermy
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MRI Tomography
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Inductive Diathermy
Questão 52
Questão
Deep heating of tissues (Therapeutic Diathermia) is applied using a high frequency current of the order of:
Responda
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0.3 - 5 Hz
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0.3 - 5 kHz
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0.3 - 5 MHz
Questão 53
Questão
High frequency AC is less harmful to the body than low frequency AC. This is because high frequency AC:
Questão 54
Questão
Microwave diathermy uses frequency of 2.450 GHz. This frequency is:
Responda
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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
Questão 55
Questão
What type of accident is most common during microwave diathermy:
Questão 56
Questão
The most prominent effect of DC on the human body is:
Responda
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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.
Questão 57
Questão
Which of the following effects is NOT characteristic for AC
Responda
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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
Questão 58
Questão
Which of the following effects is characteristic for low frequency (50 Hz) alternative current:
Responda
-
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
Questão 59
Questão
Which of the following effects is characteristic of high frequency (2 MHz) alternative current:
Responda
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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.
Questão 60
Questão
Which therapeutic method causes deep tissue heating:
Questão 61
Questão
UHF with high frequency electromagnetic waves (= GHz) are used in:
Responda
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Faradizations
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Diathermia
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Microwave Therapy
Questão 62
Questão
Negative, light aeroions have:
Responda
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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.
Questão 63
Questão
Positive Aeroions have:
Responda
-
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
Questão 64
Questão
The franklinization (electric shower) is a method in:
Responda
-
Thermal therapy using infared rays
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Patient preparation for diagnostic imaging
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Artificial aeroionotherapy
Questão 65
Questão
In the Franklilization (electric shower) the negative electrode is:
Questão 66
Questão
Favorable effect on the organism have:
Responda
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Light positive aeroions
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Light negative aeroions
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None of the aeroions
Questão 67
Questão
The concentration of light, negative aeroions is higher in:
Responda
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In the forest
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Small village
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Industrial Town
Questão 68
Questão
Iontophoresis uses:
Questão 69
Questão
Iontophoresis is a method for:
Questão 70
Questão
During Iontophoresis, if active pharmaceutical ion is positive, the active electrode is:
Responda
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The anode (positive)
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The Cathode (negative)
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Either anode with work
Questão 71
Questão
What is the difference between Sonophoresis and Iontophoresis:
Responda
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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.
Questão 72
Questão
The constant magnetic field applied to the patient in MRI examination is:
Responda
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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.
Questão 73
Questão
What part of the hydrogen nuclei (protons) are examined tissues participates in the processes of forming a diagnostic image:
Questão 74
Questão
In order to observe the phenomenon of Nuclear Magnetic Resonance (NMR), in an atomic nucleus must be:
Questão 75
Questão
The contrast between different biological tissues in MRI is obtained from:
Responda
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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)
Questão 76
Questão
Medicinal Substances with anti-oxidation properties are analysed using:
Questão 77
Questão
The chemical shift is an important parameter for direct observation of the chemical basis of disease, in:
Questão 78
Questão
Which is the most common contrast substance used in MRI
Questão 79
Questão
Volume Concentration of Protons is a parameter in diagnostic image formation in:
Questão 80
Questão
Contrast substances used MRI are:
Responda
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Paramagnetic
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Piezocrystals
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Photosensitive
Questão 81
Questão
Contrast substances used in MRI diagnostics modify:
Responda
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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
Questão 82
Questão
Longitudinal time of relaxation T1 is a parameter used in:
Responda
-
Positron Emission Tomography
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Echography
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Magnetic Resonance Tomography
-
Roentgen Computed Tomography
Questão 83
Questão
Transversal time of relaxation T2 is parameter used in:
Questão 84
Questão
In MRI, the electric signals from different small volume elements (voxels) in examined tissues are distinguished by:
Responda
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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
Questão 85
Questão
The effect of the high frequency electromagnetic field on examined tissues in MRI is:
Questão 86
Questão
For which of the listed below organs and tissues, is MRI the most informative diagnostic imagine method:
Responda
-
Soft Tissues
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Bones
-
Body Cavities
Questão 87
Questão
MRI coil magnets operate at very low temperature (in liquid helium) so that:
Responda
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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.