Quiz
PMU - Year 1 Physics - Part 2
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Perguntas do quiz (87)
1Which substances have both intrinsic, and extrinsic electric conductivity:
- AConductors
- BDielectrics (insulators)
- CSemiconductors
2Dielectrics can be described as having:
- AFree electron states in the valence band
- BWide (forbidden) band gap, and completely occupied valence band
- CExtrinsic atoms from elements with different valance
3P-doping of semiconducting germanium (Ge), will create additional energy levels;
- ANear the conduction band of Ge
- BAt the forbidden band-gap of Ge
- CNear the valence band of Ge
4The band-gap width of a dielectric (insulator) is:
- ANarrower than 1 eV
- BWider than 3 eV
- CNarrower than 0.01 eV
5Band theory of solids defines conductors as having:
- AAn unoccupied (free) electrons states in the valence band
- BA narrow band-gap, and absence of free states in the valence band
- Cimpurities from elements with lower valence
6N-doping of semiconducting germanium (Ge), will create additional energy levels:
- ANear the valence band of Ge
- BAt the forbidden bang-gap of Ge
- CNear the conduction band of Ge
7Valence and conductivity bans overlap partially in:
- AMetals
- BDielectrics
- CSemiconductors
8Charge carriers of certain type (n or p) will dominate in a semiconductor when:
- AThe number of unoccupied electron states in valence and conduction bands are equal
- BThe band-gap is large, and the valence band is completely occupied
- CImpurities with lower or higher valence are present
9What is the difference between dielectrics and semiconductors, according to band theory of solids.
- AThe number of electrons in valence band
- BBand-gap is greater or less than 3 eV in width
- CThe number of occupied electron in conduction band
10Current carriers in semiconductors are:
- AHoles only:
- BElectron and Holes
- CElectrons only
11What type of current carriers are the holes:
- APositrons
- BUnoccupied electron place-holders (virtual positive charges)
- CPositive Ions
12How does intrinsic conductivity of semiconductors depend on temperature?
- AIt increases with Temperature
- BIt decreases with Temperature
- CIt does not depends on Temperature
13How does intrinsic conductivity of semiconductors depend on Temperature?
- AA narrower band-gap results in higher conductivity.
- BA narrower band-gap results in lower conductivity.
- CIt does not depend on the width of the band-gap.
14What are the current carriers in a P-N junction, upon application of forward bias?
- AElectrons and Holes
- BOnly Electrons
- COnly Holes
15Using OHM's LAW: In order to assess the medicinal effect of a substance, in dermatology, the skin impedance Z is studied by:
- AElectromagnetic Waves
- BAn Alternating Electric Current
- CA Direct Electric Current
- DA Magnetic Field
16The electric impedance of biological tissues is composed of:
- AR and Xc
- BXL and Xc
- CR and XL
17Using OHM's LAW: Capacity reactance of an AC circuit is equal to:
- AwL + 1/wC
- B1/wC
- CwL
18Using OHM's LAW: The direction of electrical current fluctuates with time in:
- AOne-way rectified current
- BDirect Current
- CAlternating Current
19Using OHM's LAW: Ohm's law states:
- AU = IR
- BR = I/U
- CR = UI
20Using OHM's LAW: Electric current is:
- AA flow of elementary particles
- BA flow of charged particles
- CAn electromagnetic wave
21The unit for electrical conductivity is:
- AOhm
- BElectrical conductivity is a dimensionless
- CSiemens [S]
22The unit for electrical resistance is:
- AVoltage
- BAmpere
- COhm
23What type of tissue or body fluid have the highest electrical conductivity:
- ACerebrospinal fluid
- BBlood Plasma
- CBlood
- DSkin and Bones
24What is the frequency of direct currents (DC)
- A50 MHz
- B50 Hz
- CDC has no frequency
25What type of electrical current is a lightning bolt?
- ADirect current (DC)
- BHigh Frequency AC
- CLow Frequency AC
26What type of electrical current is a galvanic current?
- AHigh Frequency AC
- BLow Frequency AC
- CLow Direct Current
27What type of electric impedance is present in the human tissue?
- AInductive and Capacitive
- BResistive and Capacitive
- CResistive and Inductive
28What type of electric impedance is present in the human tissue?
- ADirect Current Only
- BAlternating Current Only
- CBoth, AC and DC can propagate
- DNeither, only electromagnetic waves can propagate.
29Transducer is a device for:
- AGeneration of metastable radionuclides
- BTransformation of energy from one form to another
- COther name of linear scanner
30What type of transducer is the piezoelectric crystal? (e.g. transducers in echo-graphs)
- AGenerator type
- BBoth Parametric and Generator Type
- CParametric Type
31What type of transducer is the ionization chamber:
- AParametric type
- BBoth Parametric and Generator Type
- CGenerator type
32Which of the objects mentioned below is a transducer:
- APermanent magnet of MRI
- BRoentgen film
- CGeiger-Muller Counter
- DMercury Thermometer
33Which of the objects mentioned below is NOT a transducer:
- AThe ionization chamber
- BThe Roentgen Film
- CThe Geiger-Muller Counter
- DThe pressure gauge of the blood pressure measuring device
34Which of the following functions are performed by a photocell:
- AIt converts chemical energy into electrical energy
- BIt converts magnetic energy into electrical energy
- CIt converts light energy into electrical energy
- DIt converts electrical energy into light energy.
35Thermocouple is an arrangement of two different metals:
- ATo convert heat into electric energy
- BTo convert heat into chemical energy
- CTo convert electrical energy into heat
36Which of the following is NOT a transducer
- AThe battery of cardiac pacemaker
- BThe thermistor
- CThe photoelectric cell
37Which is the most relevant electromyography parameter for determination of damaged tissue
- ARheobase
- BChronaxie
- CCoefficient of accommodation
38In an active electro-diagnostics the source of E.M.F (Electromotive Force):
- AThe body of the examined patient
- BThe electrocardiograph
- CThe stimulation apparatus
- DThe electroencephalograph
39In a passive electro-diagnostics the course of Electromotive Force is:
- AThe body of the examined patient
- BThe Electrocardiograph
- CThe Stimulation apparatus
- DThe Electroencephalograph
40ECG is a method of:
- AExamination of muscles
- BExamination of the brain
- CExamination of the heart
41EEG is a method of:
- AExamination of muscles
- BExamination of the brain
- CExamination of the heart
42EMG is a method of:
- AExamination of the muscles
- BExamination of the brain
- CExamination of the heart
43The active electro-diagnostic differs from the passive one in the fact that source of Electromotive Force:
- AThe electromyography
- BThe examined organ in the patient's body
- CApparatus used for electro-stimulation
44The defibrillator is used to:
- AReplace the heart in operations of the heart
- BRestore the rhythmical contraction and relaxation of the different structures of the heart muscle (the myocard)
- CSupport the cardiac output
45The cardio-stimulator (the pacemaker) is:
- ASelf-recording device for measurement of the pulse and blood pressure
- BSubstitute of the heart in operations of the heart
- CGenerator of electric impulses needed for the cardiac output.
46The cardio-stimulator (the pacemaker) is supplied by:
- ABiogalvanic elements
- BSmall battery installed beneath the patients skin
- CThe cosmic radiation
47For electrostimulation on an object to occur, a minimum threshold stimulus is needed. This electrical stimulus depends on:
- AElectrical pulse current
- BElectrical pulse duration
- CBoth, current and pulse duration.
48Faradization is a method for:
- AElectro-gymnastics using low frequency pulsed current
- BTherapy using high frequency electric current
- CDeep electro-stimulation with two interfering currents, with frequencies 2 - 5 kHz
49Microwave therapy uses:
- AElectric field generated by an electric current with a frequency of 50 hZ
- BMagnetic field generated by a direct electric current
- CHigh frequency electromagnetic waves
50The most suitable frequency magnetic field is used in:
- A20 Hz
- B20 kHz
- C20 MHz
51High Frequency magnetic field is used in:
- ACapacitive Diathermy
- BMRI Tomography
- CInductive Diathermy
52Deep heating of tissues (Therapeutic Diathermia) is applied using a high frequency current of the order of:
- A0.3 - 5 Hz
- B0.3 - 5 kHz
- C0.3 - 5 MHz
53High frequency AC is less harmful to the body than low frequency AC. This is because high frequency AC:
- AIncreases exposure time
- BPasses through the skin without irritation
- CChanges ion polarization
54Microwave diathermy uses frequency of 2.450 GHz. This frequency is:
- AHigher than microwave oven frequency
- BLower than microwave oven frequency
- CThe same as microwave oven frequency
55What type of accident is most common during microwave diathermy:
- AElectrocution
- BBurning
- CNeuromuscular Stimulation
56The most prominent effect of DC on the human body is:
- AConstant orientation of ions (polarization), followed by accommodation
- BContinuous change of polarity and lack of accommodation
- CVibration of ions around equilibrium position, rotation of electrical dipoles
- DPropagation through skin with irritation.
57Which of the following effects is NOT characteristic for AC
- AConstant orientation of ions (polarization), followed by accommodation
- BContinuous change of polarity and lack of accommodation
- CVibration of ions around equilibrium position, rotation of electrical dipoles
- DPropagation through the skin without irritation
58Which of the following effects is characteristic for low frequency (50 Hz) alternative current:
- AConstant orientation ions (polarization), followed by accommodation.
- BIons vibrate around equilibrium position, electrical dipoles rotate
- CPasses through the skin with irritation and causes deep heating
59Which of the following effects is characteristic of high frequency (2 MHz) alternative current:
- AConstant orientation ions (polarization), followed by accommodation.
- BIons vibrate around equilibrium position, electrical dipoles rotate
- CPasses through the skin without irritation and causes deep heating.
60Which therapeutic method causes deep tissue heating:
- AHigh frequency therapy using electric current
- BThermovision
- CDeep roentgen therapy
61UHF with high frequency electromagnetic waves (= GHz) are used in:
- AFaradizations
- BDiathermia
- CMicrowave Therapy
62Negative, light aeroions have:
- AA favorable effect on humans
- BA negative biological effect on humans
- CA favorable effect if they are attached to dust particles.
63Positive Aeroions have:
- AA favorable effect on humans
- BA negative biological effect on humans
- CA favorable effect if they are attached to dust particles
64The franklinization (electric shower) is a method in:
- AThermal therapy using infared rays
- BPatient preparation for diagnostic imaging
- CArtificial aeroionotherapy
65In the Franklilization (electric shower) the negative electrode is:
- AConnected to patients chair
- BAbove patients head
- COn the stage where the patients has stepped
66Favorable effect on the organism have:
- ALight positive aeroions
- BLight negative aeroions
- CNone of the aeroions
67The concentration of light, negative aeroions is higher in:
- AIn the forest
- BSmall village
- CIndustrial Town
68Iontophoresis uses:
- AUS
- BRadioactive sources
- CDirect electric current
- DAlternating electric current
69Iontophoresis is a method for:
- AElectrodiagnostics
- BElectrostimulation
- CElectrotherapy with drugs
70During Iontophoresis, if active pharmaceutical ion is positive, the active electrode is:
- AThe anode (positive)
- BThe Cathode (negative)
- CEither anode with work
71What is the difference between Sonophoresis and Iontophoresis:
- AThe former is therapeutic and the latter is diagnostic
- BThe external (physical) stimulus, enabling the insertion of drugs into the tissue
- CThe location of application.
72The constant magnetic field applied to the patient in MRI examination is:
- AWeaker than the earths magnetic
- BMuch stronger than the earths magnetic field
- CEqual to the Earths magnetic field.
73What part of the hydrogen nuclei (protons) are examined tissues participates in the processes of forming a diagnostic image:
- AAll protons
- BMinor part (about 0.0001%)
- CAll protons from the water molecules.
74In order to observe the phenomenon of Nuclear Magnetic Resonance (NMR), in an atomic nucleus must be:
- AMetastable
- BRadioactive
- CWith a magnetic moment other than zero
75The contrast between different biological tissues in MRI is obtained from:
- AThe decay of electromagnetic waves, passing through them.
- BThe difference in density p of tissues
- CThe difference in volume concentrations of hydrogen nuclei (proton)
76Medicinal Substances with anti-oxidation properties are analysed using:
- ANuclear Magnetic Resonance
- BElectronic Paramagnetic Resonance
- CRadionuclide Methods
- DColour Doppler
77The chemical shift is an important parameter for direct observation of the chemical basis of disease, in:
- ASPECT - Single Photo Emission Computer Tomography
- BPET - Positron Emission Tomography
- CCT - Computed Tomography
- DSpectroscopic MRI
78Which is the most common contrast substance used in MRI
- A99m TC
- B60Co
- C64Gd
- D10B
79Volume Concentration of Protons is a parameter in diagnostic image formation in:
- ATechnography
- BMagnetic Resonance Tomography MRI
- CPositron Emission Tomography - PET
- DRoentgenography
80Contrast substances used MRI are:
- AParamagnetic
- BPiezocrystals
- CPhotosensitive
81Contrast substances used in MRI diagnostics modify:
- AThe size of the external magnetic field
- BThe density of protons p in the examined tissue
- CThe times of relaxation T1 and T2 in the examined tissues.
- DThe frequency of the high frequency electromagnetic field
82Longitudinal time of relaxation T1 is a parameter used in:
- APositron Emission Tomography
- BEchography
- CMagnetic Resonance Tomography
- DRoentgen Computed Tomography
83Transversal time of relaxation T2 is parameter used in:
- APositron Emission Tomography
- BEchography
- CMRI
- DRoentgen Computed Tomography (CT)
84In MRI, the electric signals from different small volume elements (voxels) in examined tissues are distinguished by:
- AThe applied gradient magnetic fields
- BChange in the frequency of the high frequency electromagnetic field
- CIntroduction (injection) of contrast substance
85The effect of the high frequency electromagnetic field on examined tissues in MRI is:
- ADangerous heating
- BInsignificant endogenic heating
- CElectric Excitation
86For which of the listed below organs and tissues, is MRI the most informative diagnostic imagine method:
- ASoft Tissues
- BBones
- CBody Cavities
87MRI coil magnets operate at very low temperature (in liquid helium) so that:
- AThe risk of tissue damage is reduced
- BThe constant magnetic field is homogenous
- CA superconductivity is achieved - Magnetizing coil wires are very thin.
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- All Questions uploaded word for word from MCQ book. All Credit to Authors. Mistakes due in process may have been made, use and check your work at your own discretion. Only simple writing allowed, i.e Superscript and Subscript absent. Questions missed due to Figure/Diagrams/Text: 15. 16. 23. 24. 34. 77.
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