Download Oral Radiology- Physics MCQs
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Oral Radiology Physics MCQs Practice
1. Which statement BEST describes matter?
· Composed
of electrically neutral atoms.
· May
be subdivided by chemical methods.
· Anything
that has mass and occupies space.
· Contains
inner structures that can be divided.
2. Which nucleus component of the atom determines the
identity of the element?
· The
number of quarks.
· The
number of protons.
· The
number of leptons.
· The
number of neutrons.
3. What determines the atomic mass of an atom?
· Force
carrier particles.
· Quarks,
both up and down.
· Orbital
strength of the electrons.
· Total
number of protons and neutrons.
4. The Quantum Mechanical Model describes contemporary
understanding of the
· structure
of the nucleus.
· force
carrier particles.
· arrangement
of electrons in an atom.
· fundamental
matter particles and corresponding antiparticles.
5. Atoms have a maximum number of how many known orbitals?
· 5.
· 7.
· 10.
· 12.
6. Which statement BEST describes the amount of energy
required to remove an electron from a given orbital?
· Exceeds
the electrostatic force of attraction.
· Magnitude
related to greater distance from nucleus.
· Lost
energy in the form of electromagnetic radiation.
· Lowest
principal quantum number, then lowest angular momentum.
7. The specific balance between the positively charged
nucleus and the surrounding negatively charged electrons is called
· force
carrier particles.
· characteristic
radiation.
· electron
binding energy.
· electromagnetic
radiation.
8. The process resulting in the disruption of the electrical
neutrality of the atom is called
· ionization.
· particulate
radiation.
· radioactivity.
· electromagnetic
radiation.
9. Loosely bound electrons can be displaced by which low
energy radiation?
· Infrared.
· Ultraviolet.
· Visible
light.
· Microwave.
10. Which type of particle is used in the treatment of skin cancers?
· γ.
· χ.
· α.
· β.
11. Linear energy transfer (LET) of particulate radiation refers to
· conversion
state.
· rate
of loss of energy.
· ionization
capabilities.
· penetration
ability of radioactivity.
12. Examples of electromagnetic radiation include all EXCEPT one. Which
one is the EXCEPTION?
· Visible
light.
· b.
Radio waves.
· c.
MR imaging.
· d.
Beta particles.
13. Bundles of energy are called
· photons.
· b.
radioactive.
· c.
wave theory.
· d.
electron volts.
14. The amount of energy acquired by one electron accelerating through a
potential difference of 1 volt is called the
· electron
volt.
· b.
linear energy transfer.
· c.
radioactivity potential.
· d.
wavelength to energy relationship.
15. Which is a property of electromagnetic waves?
· Cause
ionization.
· b.
Have mass and weight.
· c.
Travel at the velocity of light in a vacuum.
· d.
Do not cause biologic changes in living cells.
16. Which unit is typically used to characterize low-energy photons such
as radio waves?
· Energy.
· b.
Direction.
· c.
Frequency.
· d.
Wavelengths.
17. Which are the primary components of an x-ray machine?
· Cathode
and anode.
· b.
Tube head and filters.
· c.
Control panel and collimator.
· d.
X-ray tube and power supply.
18. Which component of the x-ray machine is necessary in order to
generate and accelerate electrons?
· Focal
spot.
· b.
Power supply.
· c.
Tube vacuum.
· d.
Focusing cup.
19. Which is the source of electrons within the x-ray tube?
· Anode.
· b.
Filament.
· c.
Control panel.
· d.
Focusing cup.
20. The number of electrons emitted is determined by the
· thermal
conductor.
· b.
high-voltage source.
· c.
temperature of the filament.
· d.
material composing the filament.
21. The focusing cup is made of
· copper.
· b.
granite.
· c.
tungsten.
· d.
molybdenum.
22. Which is the purpose of the target in an x-ray tube?
· Remove
generated heat.
· b.
Stop production of electrons.
· c.
Convert electrons into x-ray photons.
· d.
Aim the electrons toward the area to be imaged.
23. All are characteristics of ideal target material EXCEPT one. Which
one is the EXCEPTION?
· High
melting point.
· b.
High vapor pressure.
· c.
High atomic number.
· d.
High thermal conductivity.
24. Copper and which other component of the x-ray machine tube head
dissipates heat?
· Insulating
oil.
· b.
Metal housing.
· c.
Glass envelope.
· d.
Electronic focusing cup.
25. Which is the purpose of a rotating anode?
· Increase
production of x-rays.
· b.
Decrease number of electrons.
· c.
Eliminate need for angled target.
· d.
Dissipate heat from small focal spot.
26. Which type of x-ray machine utilizes a stationary anode?
· Intraoral.
· b.
Tomographic.
· c.
Cephalometric.
· d.
Medical computed tomography.
27. The flow of electrons from the cathode filament, across the tube to
the anode, and then back to the filament is called the
· voltage.
· b.
tube current.
· c.
x-ray production.
· d.
filament transformer.
28. Which x-ray machine control regulates the filament temperature?
· On/off
switch.
· b.
Exposure time.
· c.
Milliamperage (mA).
· d.
Kilovolt peak (kVp).
29. Which x-ray machine control converts the primary voltage from the
input source into the desired secondary voltage?
· On/off
switch.
· b.
Exposure time.
· c.
Milliamperage (mA).
· d.
Kilovolt peak (kVp).
30. Which is an advantage of a constant-potential x-ray machine over a
self-rectifying x-ray machine, given a voltage and radiographic density
setting?
· Lower
patient radiation dose.
· b.
Increased radiation production.
· c.
More efficient use of electricity.
· d.
Effective use of inverse voltage.
31. Which x-ray machine control limits the duration of x-ray production?
· On/off
switch.
· b.
Exposure time.
· c.
Milliamperage (mA).
· d.
Kilovolt peak (kVp).
32. How many impulses of radiation equivalent occur in a one-fourth (1 4
) second exposure?
· 9.
· b.
15.
· c.
20.
· d.
30.
33. Which is the approximate heat storage capacity for anodes in dental
x-ray tubes?
· 5
kHU.
· b.
15 kHU.
· c.
20 kHU.
· d.
30 kHU.
34. Which factor determines the interval between successive x-ray
exposures?
· kVp.
· b.
Exposure time.
· c.
Heat dissipation.
· d.
Number of electrons.
35. Which is the primary form of radiation produced from an intraoral
x-ray tube?
· Particulate.
· b.
Secondary.
· c.
Characteristic.
· d.
Bremsstrahlung.
36. When an electron from the filament directly hits the nucleus of a
target atom, which entity is produced?
· New
atom.
· b.
Single x-ray photon.
· c.
Decelerated electron.
· d.
Characteristic radiation.
37. Which statement does NOT explain the continuous spectrum of x-ray
photons?
· Accelerated
electrons form characteristic radiation.
· b.
Deflected electrons give up varying amounts of energy.
· c.
Electrons striking the target have varying levels of kinetic energy.
· d.
Electrons participate in many bremsstrahlung interactions before losing all
their kinetic energy.
38. Which occurs when an electron is ejected from its orbital by an
incident electron?
· Particulate
radiation.
· b.
Secondary radiation.
· c.
Characteristic radiation.
· d.
Bremsstrahlung radiation
39. Doubling the exposure time will result in which occurrence?
· Doubling
the range of photon energies.
· b.
Doubling the number of photons generated.
· c.
Decreasing by half the x-ray emission spectrum.
· d.
Decreasing by half the number of electrons produced.
40. The beam intensity is affected by all factors EXCEPT one. Which one
is the EXCEPTION?
· Collimation.
· b.
Exposure time.
· c.
Tube current (mA).
· d.
Tube voltage (kVp).
41. Which statement BEST describes the half-value layer (HVL)?
· Inherent
filtration used to decrease beam intensity by one half.
· b.
Increased beam intensity to compensate for one half reduction due to distance.
· c.
Thickness of absorber necessary to reduce the number of x-ray photons by one
half.
· d.
Total filtration necessary to compensate for increased number of electrons
produced.
42. Which is the purpose of dental x-ray machine filtration?
· Decrease
beam intensity.
· b.
Reduce the size of the x-ray beam.
· c.
Regulate the shape of the x-ray beam.
· d.
Eliminate low-energy photons.
43. According to government regulations, the total filtration for a
dental x-ray machine set at 69 kVp should be
· mm.
· b.
1.5 mm.
· c.
2.0 mm.
· d.
2.5 mm.
44. Which is the purpose of collimation of the x-ray beam?
· Direct
photons.
· b.
Intensify beam.
· c.
Reduce exposure area.
· d.
Adjust for source-to-point distance.
45. If the source-to-point distance is increased, then which adjustment
should be made to ensure consistent image density?
· Increase
kVp.
· b.
Decrease mA.
· c.
Increase exposure time.
· d.
Decrease added filtration.
46. If a dose of 2 Gy is measured at a distance of 4 m, then which is the dose
found at 2 m?
· 0.25
Gy
· b.
0.50 Gy
· c.
4 Gy
· d.
8 Gy
47. During patient exposure, absorption interactions of photons will do
all EXCEPT one. Which one is the EXCEPTION?
· Cease
to exist.
· b.
Ionize absorber atoms.
· c.
Produce a homogenous beam.
· d.
Convert energy into ejected electron energy.
48. During patient exposure, which type of beam attenuation occurs MOST
frequently?
· Coherent
scattering.
· b.
Compton scattering.
· c.
Photoelectric absorption.
· d.
Bremsstrahlung radiation.
49. A photoelectric interaction is MOST LIKELY to occur when photons
interact with which tissue?
· Bone.
· b.
Dentin.
· c.
Soft tissue.
· d.
Tooth pulp.
50. The probability of a Compton interaction is directly proportional to
which entity?
· Source-to-point
distance.
· b.
Electron density of the absorber.
· c.
Third power of the atomic number of the absorber.
· d.
Interaction of a low-energy incident photon with an outer electron.
51. The absorption of the x-ray beam depends upon all factors EXCEPT one.
Which one is the EXCEPTION?
· Energy
of beam.
· b.
Density of absorber.
· c.
Thickness of absorber.
· d.
Half-value layer of beam.
52. Determining the quantity of radiation exposure is called
· filtration.
· b.
dosimetry.
· c.
ionization.
· d.
K-edge absorption.
53. A measure of the capacity of radiation to ionize air is called
· exposure.
· b.
absorbed dose.
· c.
equivalent dose.
· d.
radioactivity level.
54. Which unit is used to compare the high linear energy transfer (LET)
of particulate radiations to a lower-LET radiation such as x-rays?
· Exposure
dose.
· b.
Absorbed dose.
· c.
Equivalent dose.
· d.
Effective dose.
55. Which unit is used to compare the risk of radiation exposure of one
part of the body to another part?
· Exposure
dose.
· b.
Absorbed dose.
· c.
Equivalent dose.
· d.
Effective dose.
56. The traditional unit called radiation absorbed dose (rad) is
expressed in the SI system as
· gray
(Gy).
· b.
sievert (Sv).
· c.
becquerel (Bq).
· d.
coulomb/kilogram (C/kg).