PMU - Year 1 Physics - Part 4(A)

Question 1 of 69

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Protons and neutrons in a nucleus are termed:

Select one of the following:

  • Beta-particles

  • Photons

  • Nucleons

Question 2 of 69

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Linear attenuation coefficient of photoelectric absorption (photoelectric effect interaction probability) τ is:

Select one of the following:

  • Inversely proportional to the atomic number of the element Ζ

  • Inversely proportional to the mass number A

  • Proportional on the density ρ

Question 3 of 69

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Linear attenuation coefficient of photoelectric absorption τ depends strongly (approximately to the 4-th power) on:

Select one of the following:

  • The density of substance

  • The atomic number of element Z

  • The temperature of substance - t

Question 4 of 69

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Linear attenuation coefficient for Compton effect (Compton scattering interaction probability) δ is proportional to:

Select one of the following:

  • Atomic mass number A

  • Density of substance

  • The ratio A/Z

Question 5 of 69

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Linear attenuation coefficient for Compton effect is proportional to:

Select one of the following:

  • pZ4

  • pZ2

  • pZ/A

Question 6 of 69

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Linear attenuation coefficient for pair production (electron-positron production probability) X is proportional to:

Select one of the following:

  • Atomic mass number A

  • The square of the atomic number of the element Z2

  • The ratio of A/Z

Question 7 of 69

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Predominant mode of interaction between conventional diagnostic x-ray and biological tissues (Figure 11. not included) is:

Select one of the following:

  • Pair production (electron-positron)

  • Photoelectric absorption

  • Compton effect (scattering)

Question 8 of 69

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Interaction of photonic ionizing radiation with matter will

Select one of the following:

  • Reduce radiation intensity

  • Not change radiation intensity

  • Increase radiation intensity

Question 9 of 69

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What type of interaction between diagnostic x-rays and matter is improbable:

Select one of the following:

  • Photoelectric absorption

  • Pair production (electron-positron)

  • Compton effect

Question 10 of 69

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Consider attenuation of photon beam in water/soft tissue (figure 11. not included). Which statement is true:

Select one of the following:

  • Photons may undergo two successive photoelectric transitions

  • Compton scattering has a threshold energy of 1.022 MeV

  • Photoelectric effect increases with photo energies

  • Photoelectric and Compton effects equal at 25 KeV

Question 11 of 69

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Roentgen Rays are:

Select one of the following:

  • Photons

  • Electrons

  • Positrons

Question 12 of 69

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Roentgen rays are:

Select one of the following:

  • Electromagnetic Radiation:

  • Protons

  • Electrons

Question 13 of 69

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X-rays have

Select one of the following:

  • A wavelength longer than that of the visible light

  • Positive Electric Charge

  • Ionizing Capacity

Question 14 of 69

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The wavelength of the roentgen radiation is within the range of:

Select one of the following:

  • 380 - 760 nm

  • 0.76 - 1000 µm

  • 10 - 380 µm

  • Less than 10 nm

Question 15 of 69

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X-rays have:

Select one of the following:

  • Frequency higher than that of the visible light

  • Direct ionizing capacity

  • Negative electric charge

Question 16 of 69

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Characteristic x-ray radiation:

Select one of the following:

  • Has continuous energy spectrum

  • Does not differ from braking radiation spectrum

  • Is obtained from K and L shell electron transitions from high atomic shells.

Question 17 of 69

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Continuous x-ray energy spectrum:

Select one of the following:

  • Contains several photons with different energy

  • Does not differ from the characteristic x-ray spectrum

  • Is a result of rapid deceleration of electrons near target nuclei

Question 18 of 69

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Intensity ψ of radiation in x-ray tube is proportional to:

Select one of the following:

  • The atomic number Z of anode's material

  • The 3-th power of anode U3/a

  • The 2-nd power of anode I2/a

Question 19 of 69

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Intensity ψ of roentgen radiation (x-ray tube) is proportional to:

Select one of the following:

  • The 3-th power of anode voltage U3/a

  • The anode current Ia

  • The 2-nd power of the atomic number Z2 of anodes material.

Question 20 of 69

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Intensity ψ of roentgen radiation (x-ray tube) if proportional to:

Select one of the following:

  • Density p of the cathode material

  • The 2-nd power of anode voltage U2/a

  • The 2-nd power of anode current I2/a

Question 21 of 69

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Minimum wavelength λmin (maximum energy) of x-ray tube radiation depends on:

Select one of the following:

  • Anode Voltage Ua

  • Anode current

  • The atomic number Z of the element of which anode is made

  • Density p of the material of which cathode is made

Question 22 of 69

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Filters in x-ray apparatus modify:

Select one of the following:

  • The minimum wavelength λmin of x-ray braking spectrum

  • The amount of anode Voltage Ua

  • The intensity ψ of roentgen radiation

Question 23 of 69

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Intensity ψ of the Roentgen rays is proportional to:

Select one of the following:

  • U2IZ

  • UI2Z

  • UIZ2

Question 24 of 69

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Hardness of x-ray radiation (harder/softer) is changed by:

Select one of the following:

  • Anode voltage Ua

  • Beam intensity ψ

  • Anode current Ia

Question 25 of 69

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The relationship between HVL (Half Value Layer) and linear attenuation coefficient µ is

Select one of the following:

  • HVL = ln(2)/µ

  • HVL = µ/ln(2)

  • HVL = µ*ln(2)

Question 26 of 69

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Water is said to be soft tissue equivalent with respect to x-ray attenuation. This is because water and soft tissue have approximately the same properties. Which properties are NOT the same? (there are more than one correct answers)

Select one of the following:

  • Effective atomic number Zeff

  • Effective molecular weight

  • Physical density p

  • Attenuation Coefficient µ

Question 27 of 69

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The purpose of the introduction of contrast substances in the roentgen diagnostics is to:

Select one of the following:

  • Obtain coloring in the roentgenogram and not only black and white images

  • Increasing the contrast between soft tissues

  • Reduce the radiation dose on patients

Question 28 of 69

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Contrast substances in diagnostics radiology will:

Select one of the following:

  • Increase contrast between different soft tissues

  • Increase contrast between soft tissues and bones

  • Obliterate cancer cells

Question 29 of 69

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Which of the listed chemical elements provides maximum contrast in diagnostic radiology:

Select one of the following:

  • Calcium: Z = 20, p = 1.55 g/cm3

  • Barium: Z = 56, p = 3.5 g/cm3

  • Iodine: Z = 53, p = 4.94 g/cm3

Question 30 of 69

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Roentgen osteo-densitometry (measurement of bone density) is based on which of the following phenomena:

Select one of the following:

  • Diffraction of roentgen rays (x-rays)

  • Scattering of roentgen rays (x-rays)

  • Attenuation of Roentgen rays (x-rays)

Question 31 of 69

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Hounsfield Unit (CT number) for bones is equal to:

Select one of the following:

  • 0

  • up to (+3000)

  • (-1000)

Question 32 of 69

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Hounsfield unit (CT number) for air is equal to:

Select one of the following:

  • 0

  • Up to (+3000)

  • (-1000)

Question 33 of 69

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Hounsfield unit (CT number) for water is equal to:

Select one of the following:

  • 0

  • up to (+3000)

  • (-1000)

Question 34 of 69

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Hounsfield unit (CT number) is defined as:

Select one of the following:

  • (µ-tissue + µ-water) / µ-water

  • (µ-tissue - µ-water) / µ-water

  • (µ-tissue - µ-water) / µ-tissue

Question 35 of 69

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Predominant x-ray interaction mode in CT scanning is:

Select one of the following:

  • Photoelectric absorption & compton scattering

  • Electron-positron pair production & photoelectric absorption

  • Compton scattering & electron-positron pair production

Question 36 of 69

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CT diagnostic imaging is based on the phenomenon of:

Select one of the following:

  • Reflection of reoentgean rays at the boundary between different structures

  • Absorption of roentgen rays by tissues exposed to radiation

  • Attenuation of roentgen rays by tissues exposed to radiation

Question 37 of 69

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What is the meaning of "computed" in name of CT (computed tomography)?

Select one of the following:

  • Calculation of radiation dose

  • Control of the scanning process

  • Formation of the final image

Question 38 of 69

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Computed tomography uses higher anode voltage compared to conventional roentgenography because

Select one of the following:

  • Patients are placed further away from x-ray source

  • Rotation of x-ray tube exposes more massive parts of patients body radiation

  • CT x-ray detectors are less sensitive

Question 39 of 69

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CT exposes pateints to higher radiation doses compared to conventional roentgenography (x-ray imaging) because:

Select one of the following:

  • Anode voltage is higher

  • Multiple images are taken

  • Both A and B

Question 40 of 69

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Radionuclides used in "in vivo" radionuclide diagnostics are:

Select one of the following:

  • Alpha-radionuclides

  • Beta-radionuclides

  • Gamma-Radionuclides

Question 41 of 69

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What type of radioactivity is related to SPECT radionuclide diagnostics:

Select one of the following:

  • Beta

  • Alpha

  • Gamma

Question 42 of 69

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Alpha-rays are a beam of:

Select one of the following:

  • Electrons

  • Helium nuclei

  • Positrons

Question 43 of 69

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Radiopharmaceuticals are:

Select one of the following:

  • Contrast substances used in MRI

  • Contact gels used in ultrasound diagnostics

  • Chemical compounds containing radioactive isotopes

Question 44 of 69

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The following quantity participates in the law of radioactive decay:

Select one of the following:

  • Huddersfield unit (CT-number)

  • Index of refreaction n

  • Linear attenuation coefficient

  • Decay constant

Question 45 of 69

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Half-life T1/2 is defined as:

Select one of the following:

  • Energy of gamma-radiation

  • Probability of radioactive decay

  • The time it takes for radioactivity to be reduced by half.

Question 46 of 69

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Isomeric transition is a type of decay that changes:

Select one of the following:

  • The atomic number Z of the element

  • The energy of the nucleus

  • The mass number A of the nucleus

Question 47 of 69

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Radionuclides produced in generators have:

Select one of the following:

  • Long half-life T1/2

  • Short half-life T1/2

  • High energy gamma-radiation

Question 48 of 69

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Radionuclide generators contain:

Select one of the following:

  • Only gamma-radionuclides

  • A meta-stable mother radionuclide

  • A metastable daughter radionuclide

  • Mother (parents) and daughter radionuclides - metastable radionuclides

Question 49 of 69

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Radionuclides are:

Select one of the following:

  • Transformers of radiowaves

  • Radioactive nuclei

  • Ultrasound detectors

Question 50 of 69

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How does activity of a radio-pharmaceutical change after sterilization for intravenous application (sterilization time ignored):

Select one of the following:

  • Reduces abruptly due to chemical changes

  • Increases abruptly due to chemical changes

  • Remains unchanged

Question 51 of 69

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Radio-pharmaceuticals used in nuclear medicine include:

Select one of the following:

  • Elements with radioactive nuclei

  • Transformers of infared rays

  • Sources of ultrasound

Question 52 of 69

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Radio-pharmaceuticals used for "in vivo" diagnostics contain radionuclides with the following mode of radioactivity:

Select one of the following:

  • Isometric Transition

  • Beta minus decay

  • Alpha decay

Question 53 of 69

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Time required for intial activity A0 for a radioactive source to decay to 10% is between:

Select one of the following:

  • 1 and 2 half-lives

  • 2 and 3 half-lives

  • 3 and 4 half-lives

  • 4 and 5 half-lives

Question 54 of 69

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The decay constant for 182TA is 0.006 day-1. Which is its half life:

Select one of the following:

  • 0.006 days

  • 83 days

  • 115 days

  • 167 days

Question 55 of 69

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The phenomenon of radioactivity is associated with:

Select one of the following:

  • Decay of atoms

  • Decay of nucleus

  • Fusion of nuclei

  • Emission of valence Orbital electrons

Question 56 of 69

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Electron capture involves:

Select one of the following:

  • An electron combining with a neutron

  • A neutron being ejected from the nucleus

  • An electron combining with a proton

  • An electron being ejected from the nucleus

Question 57 of 69

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In alpha decay:

Select one of the following:

  • Z and A are unchanged

  • Z decreases by 4 and A decreases by 2

  • Z decreases by 2 and A decreases by 4

  • Z decreases by 4 and A decreases

Question 58 of 69

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Isomeric transition involves:

Select one of the following:

  • The emission of a gamma-ray

  • The conversion of a neutron to a proton

  • The conversion of a proton to a neutron

  • Electron Capture

Question 59 of 69

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An alpha-particle consists of:

Select one of the following:

  • One proton and two neutron

  • Two proton and one neutron

  • Two proton and two neutron

  • One proton and One neutron

Question 60 of 69

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For pair production interactions it is true that:

Select one of the following:

  • Have no energy threshold

  • Occur near the electric field of the nucleus

  • Produce 1.022 MeV annihilation radiation

  • Are important in diagnostic radiology

  • All of the above

Question 61 of 69

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99Tc-m has a half-life t1/2 = 6h. What is the approximate value of 99tc-m decay constant:

Select one of the following:

  • 0.12 sec-1

  • 0.12 min-1

  • 0.12 hr-1

Question 62 of 69

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After 40 half-lives have elapsed, the activity A of radionuclide is equal to:

Select one of the following:

  • A0/40

  • A0/(2*40)

  • A0/(2 40)

Question 63 of 69

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Polonium-210 has a half-life of 4.5 months, and decays into the stable daughter isotope of lead-206. By measuring the proportion of polonium to lead in a sample, one can establiosh the production date of polonium. If the proportion is 1:15 (Po:Pb), how many months have elapsed since production date?

Select one of the following:

  • 3

  • 15

  • 18

Question 64 of 69

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What type of radiation can NOT be detected with scintillation detector?

Select one of the following:

  • Alpha particles

  • Beta Particles

  • Gamma Rays

Question 65 of 69

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Ionizing radiation used for "In vivo" radionuclide diagnostics:

Select one of the following:

  • Alpha and gamma radiation

  • Beta minus radiation

  • Gamma and annihilation radiation

Question 66 of 69

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Which quantity is NOT a parameter of radionuclides:

Select one of the following:

  • Activity A

  • Half-Life T1/2

  • Radiation yield

  • Decay constant

Question 67 of 69

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Activity A is a parameter of:

Select one of the following:

  • Laser radiation

  • Radionuclides

  • Radioactive sources

Question 68 of 69

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Why is technetium-99m (99mTC) preferred over iodine-131 (131-I) for thyroid gland diagnostics?

Select one of the following:

  • 99mTC is more cost-effective

  • 99mTC has fewer side effects

  • 99mTC is a "pure" gamma source and the radiation is orders of magnitude less

  • Natural deposits of 99mTC exists in some tissues

Question 69 of 69

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1987 an old radiotherapy source of cesium-137 (T1/2 = 30 years) was stolen from an abandoned hospital in the brazilian city of goiania. It was subsequently handled by many people, resulting in four deaths and 249 cases of high radiation exposure. If the activity of the source was 74TBq (Terebecquerels) in 1971, what was the activity in the time of the accident?

Select one of the following:

  • 51 TBq

  • 37 TBq

  • 30 TBq

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PMU - Year 1 Physics - Part 4(A)

Sole C
Quiz by , created almost 2 years ago

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: 11.44.46.57

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Sole C
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