# PMU - Year 1 Physics - Part 4(A)

Quiz by Sole C, updated more than 1 year ago
 Created by Sole C about 6 years ago
102
6

### Description

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

## Resource summary

### Question 1

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Protons and neutrons in a nucleus are termed:
• Beta-particles
• Photons
• Nucleons

### Question 2

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Linear attenuation coefficient of photoelectric absorption (photoelectric effect interaction probability) τ is:
• Inversely proportional to the atomic number of the element Ζ
• Inversely proportional to the mass number A
• Proportional on the density ρ

### Question 3

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Linear attenuation coefficient of photoelectric absorption τ depends strongly (approximately to the 4-th power) on:
• The density of substance
• The atomic number of element Z
• The temperature of substance - t

### Question 4

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Linear attenuation coefficient for Compton effect (Compton scattering interaction probability) δ is proportional to:
• Atomic mass number A
• Density of substance
• The ratio A/Z

### Question 5

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Linear attenuation coefficient for Compton effect is proportional to:
• pZ4
• pZ2
• pZ/A

### Question 6

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Linear attenuation coefficient for pair production (electron-positron production probability) X is proportional to:
• Atomic mass number A
• The square of the atomic number of the element Z2
• The ratio of A/Z

### Question 7

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Predominant mode of interaction between conventional diagnostic x-ray and biological tissues (Figure 11. not included) is:
• Pair production (electron-positron)
• Photoelectric absorption
• Compton effect (scattering)

### Question 8

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Interaction of photonic ionizing radiation with matter will

### Question 9

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What type of interaction between diagnostic x-rays and matter is improbable:
• Photoelectric absorption
• Pair production (electron-positron)
• Compton effect

### Question 10

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

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Roentgen Rays are:
• Photons
• Electrons
• Positrons

### Question 12

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Roentgen rays are:
• Protons
• Electrons

### Question 13

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X-rays have
• A wavelength longer than that of the visible light
• Positive Electric Charge
• Ionizing Capacity

### Question 14

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The wavelength of the roentgen radiation is within the range of:
• 380 - 760 nm
• 0.76 - 1000 µm
• 10 - 380 µm
• Less than 10 nm

### Question 15

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X-rays have:
• Frequency higher than that of the visible light
• Direct ionizing capacity
• Negative electric charge

### Question 16

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• 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

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Continuous x-ray energy spectrum:
• 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

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

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

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

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

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Filters in x-ray apparatus modify:
• The minimum wavelength λmin of x-ray braking spectrum
• The amount of anode Voltage Ua
• The intensity ψ of roentgen radiation

### Question 23

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Intensity ψ of the Roentgen rays is proportional to:
• U2IZ
• UI2Z
• UIZ2

### Question 24

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Hardness of x-ray radiation (harder/softer) is changed by:
• Anode voltage Ua
• Beam intensity ψ
• Anode current Ia

### Question 25

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The relationship between HVL (Half Value Layer) and linear attenuation coefficient µ is
• HVL = ln(2)/µ
• HVL = µ/ln(2)
• HVL = µ*ln(2)

### Question 26

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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)
• Effective atomic number Zeff
• Effective molecular weight
• Physical density p
• Attenuation Coefficient µ

### Question 27

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

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Contrast substances in diagnostics radiology will:
• Increase contrast between different soft tissues
• Increase contrast between soft tissues and bones
• Obliterate cancer cells

### Question 29

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

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Roentgen osteo-densitometry (measurement of bone density) is based on which of the following phenomena:
• Diffraction of roentgen rays (x-rays)
• Scattering of roentgen rays (x-rays)
• Attenuation of Roentgen rays (x-rays)

### Question 31

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Hounsfield Unit (CT number) for bones is equal to:
• 0
• up to (+3000)
• (-1000)

### Question 32

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Hounsfield unit (CT number) for air is equal to:
• 0
• Up to (+3000)
• (-1000)

### Question 33

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Hounsfield unit (CT number) for water is equal to:
• 0
• up to (+3000)
• (-1000)

### Question 34

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Hounsfield unit (CT number) is defined as:
• (µ-tissue + µ-water) / µ-water
• (µ-tissue - µ-water) / µ-water
• (µ-tissue - µ-water) / µ-tissue

### Question 35

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Predominant x-ray interaction mode in CT scanning is:
• Photoelectric absorption & compton scattering
• Electron-positron pair production & photoelectric absorption
• Compton scattering & electron-positron pair production

### Question 36

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CT diagnostic imaging is based on the phenomenon of:
• 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

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What is the meaning of "computed" in name of CT (computed tomography)?
• Control of the scanning process
• Formation of the final image

### Question 38

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Computed tomography uses higher anode voltage compared to conventional roentgenography because
• 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

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CT exposes pateints to higher radiation doses compared to conventional roentgenography (x-ray imaging) because:
• Anode voltage is higher
• Multiple images are taken
• Both A and B

Question

Question
• Beta
• Alpha
• Gamma

### Question 42

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Alpha-rays are a beam of:
• Electrons
• Helium nuclei
• Positrons

### Question 43

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• Contrast substances used in MRI
• Contact gels used in ultrasound diagnostics
• Chemical compounds containing radioactive isotopes

### Question 44

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The following quantity participates in the law of radioactive decay:
• Huddersfield unit (CT-number)
• Index of refreaction n
• Linear attenuation coefficient
• Decay constant

### Question 45

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Half-life T1/2 is defined as:
• The time it takes for radioactivity to be reduced by half.

### Question 46

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Isomeric transition is a type of decay that changes:
• The atomic number Z of the element
• The energy of the nucleus
• The mass number A of the nucleus

### Question 47

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• Long half-life T1/2
• Short half-life T1/2

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### Question 49

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• Ultrasound detectors

### Question 50

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How does activity of a radio-pharmaceutical change after sterilization for intravenous application (sterilization time ignored):
• Reduces abruptly due to chemical changes
• Increases abruptly due to chemical changes
• Remains unchanged

### Question 51

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Radio-pharmaceuticals used in nuclear medicine include:
• Transformers of infared rays
• Sources of ultrasound

### Question 52

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• Isometric Transition
• Beta minus decay
• Alpha decay

### Question 53

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Time required for intial activity A0 for a radioactive source to decay to 10% is between:
• 1 and 2 half-lives
• 2 and 3 half-lives
• 3 and 4 half-lives
• 4 and 5 half-lives

### Question 54

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The decay constant for 182TA is 0.006 day-1. Which is its half life:
• 0.006 days
• 83 days
• 115 days
• 167 days

### Question 55

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The phenomenon of radioactivity is associated with:
• Decay of atoms
• Decay of nucleus
• Fusion of nuclei
• Emission of valence Orbital electrons

### Question 56

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Electron capture involves:
• 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

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In alpha decay:
• 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

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Isomeric transition involves:
• 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

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An alpha-particle consists of:
• One proton and two neutron
• Two proton and one neutron
• Two proton and two neutron
• One proton and One neutron

### Question 60

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For pair production interactions it is true that:
• 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

Question
99Tc-m has a half-life t1/2 = 6h. What is the approximate value of 99tc-m decay constant:
• 0.12 sec-1
• 0.12 min-1
• 0.12 hr-1

### Question 62

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After 40 half-lives have elapsed, the activity A of radionuclide is equal to:
• A0/40
• A0/(2*40)
• A0/(2 40)

### Question 63

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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?
• 3
• 15
• 18

### Question 64

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What type of radiation can NOT be detected with scintillation detector?
• Alpha particles
• Beta Particles
• Gamma Rays

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### Question 66

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Which quantity is NOT a parameter of radionuclides:
• Activity A
• Half-Life T1/2
• Decay constant

### Question 67

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Activity A is a parameter of:

### Question 68

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

Question
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?
• 51 TBq
• 37 TBq
• 30 TBq

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