fundamental

Question 1

What is the neutron number of mercury?​

​8​

80​

201​

121

Answer 1

201-80=121

Question 2

What is the definition of an isotope?​

a) Same proton number so same element, but different number of neutrons​

b) Same mass number but different atomic number​

c) Same number of neutrons but different number of protons​

d) the same number of protons and neutrons but they have different amounts of energy.​

Answer 2

A

Question 3

Which force is responsible for the transformation of a neutron in to a proton?​

Nuclear force​

Strong force​

Weak force​

Electromagnetic force

Answer 3

weak

Question 4

How many electrons are in the M shell?​

25​

16​

18​

36

Answer 4

ans: 18
m is the third shell
3 squared = 9
x2= 18
2(n^2)

Question 5

Using the diagram, how much energy is released when an electron moves from L–>K?​

11eV​

69eV​

2.8eV​

58eV

Answer 5

the difference between the two shells
58eV

Question 6

what is an isobar

Answer 6

equal A. Same mass number but different atomic number​

Question 7

what is an isotone

Answer 7

same N
Same number of neutrons but different number of protons

Question 8

what is an isomer

Answer 8

In atomic physics they have the same number of protons and neutrons but they have different amounts of energy. They are in a metastable state.

Question 9

nucleons and the nucleus are held together by which force?

Answer 9

strong force

Question 10

which radioactive decay modes are isobaric?

Answer 10

the mass stays the same: isomeric transition, positron emission (peta positive), beta negative, electron capture.

Question 11

which radioactive decay types cause transmutation

Answer 11

a different element is formed: alpha decay, beta neg, beta positive, electron capture (spontaneous fission)

Question 12

below a z number of 20, what is the stable ratio of protons and neutrons?

Answer 12

1:1

Question 13

above a z number of 20, what is a stable ratio of neutrons to protons?

Answer 13

1.5:1

Question 14

what is the equation for negatron decay/ beta minus decay? when does it occur?

Answer 14

too many neutrons

Question 15

what is the equation for alpha decay? when does it occur?

Answer 15

too many nucleons- very heavy, mass over 200

Question 16

what is the equation for electron capture? when does it occur?

Answer 16

p+e-= Neutron and antineutrino. when too few neutrons
This competes with β+ decay as it also occurs in proton-rich nuclei. If the energy difference between the parent and daughter nuclides is too low for positron emission an inner shell electron is captured by the nucleus converting a proton into a neutron (i.e. positive + negative = neutral). As with β+ decay the mass number remains the same but the atomic number decreases by 1. This emission causes characteristic X-rays.

Question 17

what is the equation for beta positive decay? when does it occur?

Answer 17

too few neutrons. The extra proton decays into a neutron (which is retained in the nucleus), a positron (β+ or e) and an electron neutrino (ve). A neutron is gained, and a proton is lost meaning the mass number remains equal but the atomic number decreases by 1. This form of radioactivity, with the production of a positron, is important in PET imaging. The emitted positron travels only a minimal distance before it undergoes an annihilation reaction with the production of two 0.511 MeV photons that travel in opposite directions to one another.​

Question 18

what is isomeric transition? when does it occur?

Answer 18

A radionuclide in a metastable excited state decays to its ground state by isomeric transition and the number of protons and neutrons remain the same and the mass number and atomic number remain unchanged. Excess energy is emitted as gamma ray, internal conversion electron or both. Internal conversion is energy transfer to an orbital electron ejecting it. The ejected electron is called a conversion electron (E = gamma ray - binding E), often causes characteristic XR or Auger electron. ​e.g. technectium

Question 19

which decay produces gamma radiation?

Answer 19

isomeric transition
The ratio of protons and neutrons should mean it is stable, but it is still not in a resting state, the excess energy is given off by isomeric transition. A gamma ray is emitted. Or the nucleus undergoes internal conversion (the de- excitation energy is transferred to a K, L or M shell electron, the electron is ejected and has the kinetic energy equal to that of the gamma ray minus the electron binding energy. The vacancy created is filled by an electron cascade as previously described) .The mass number and atomic number remain unchanged.- gamma emission.
e.g. Tc-99m → Tc-99 + 140 keV γ rays

Question 20

1. What is the primary characteristic of alpha particles?​

A. High energy photons​
B. Heavy particles with a short range​
C. Light particles that can be subdivided into β+ and β-​
D. Electrically neutral particles with little mass

Answer 20

B

Question 21

2. Which of the following emissions occurs during β- decay?​

A. Helium atom​
B. Positron​
C. Electron and electron antineutrino​
D. Characteristic X-rays

Answer 21

C

Question 22

​

3. What process competes with β+ decay in proton-rich nuclei?​

A. Alpha decay​
B. Electron capture​
C. Isomeric transition​
D. Negatron decay

Answer 22

B

Question 23

​

5. What is emitted during isomeric transition?​

A. Alpha particles​
B. Helium atom​
C. Gamma rays or internal conversion electrons​
D. Positrons and neutrinos

Answer 23

C

Question 24

​

6. What is produced in positron decay that is significant for PET imaging?​

A. Characteristic X-rays​
B. Auger electrons​
C. Two 0.511 MeV photons​
D. A helium nucleus

Answer 24

C

Question 25

7. Which type of radioactive decay occurs when a neutron is converted into a proton?​ A. Beta-plus decay (β+)​ B. Beta-minus decay (β-)​ C. Alpha decay​ D. Electron capture

Answer 25

B

Question 26

8. What happens to the atomic number during electron capture?​ A. It increases by 1​ B. It decreases by 1​ C. It remains unchanged​ D. It increases by 2

Answer 26

B. a proton and electron become a neutron

Question 27

9. What type of emission results from energy transitions in the electron shell?​ A. Gamma rays​ B. Characteristic X-rays​ C. Neutrinos​ D. Beta particles​

Answer 27

B. gamma from nucleus, x rays fron electrons

Question 28

what is the unit of radioactivity

Answer 28

Unit of radioactivity: becquerel Bq. 1Bq= 1 disintegration/s mBq= megabecquerel sometimes curies (Ci) or millicuries 1mCi= 37MBq

Question 29

define specific activity

Answer 29

Definition: The rate at which a radionuclide decays per unit of mass Units: Usually given in becquerels per kilogram (Bq/kg) or curies per gram (Ci/g) Activity: the quantity of radioactive material, expressed as the number of radioactive atoms undergoing nuclear transformation per unit time (t) is called activity (A). Mathematically it is equal to the change (dN) in the total number of radioactive atoms (N) in a given time (dt) Specific activity takes in to account the weight of the radioactive material. λN divided by the weight. Therefore λN/w.

Question 30

what is the decay constant?

Answer 30

The radioactive decay constant, represented by the symbol λ, is the probability that a nucleus of a radioactive nuclide will decay in a unit of time. The decay constant is a characteristic of unstable radionuclides, which spontaneously decay into a more stable configuration. each nuclide has its own constant. another definition- the disappearance of a constant fraction of activity in a given time. Nuclear decay is a random unpredictable process. Observation of a larger number of atoms over a period of time allows an average rate of transformation (decay) to be established. The number of atoms decaying per unit time is proportional to the number of unstable atoms (N) present at any given time: dN/dt ∝N This can be changed to equality by adding a constant -dN/dt=λN--> activity.

Question 31

what is the radioactive half life?

Answer 31

Half-life is the time it takes for half of the unstable nuclei in a sample to decay or for the activity of the sample to halve or for the count rate to halve. The number of radioactive atoms remaining in the sample and the number of elapsed half lives are related by the following equation: N=N0/2 to the power n Where N is the number of atoms remaining, N0 is the initial number of radioactive atoms, and n is the number of half lives that have elapsed.

Question 32

how are half life and the decay constant linked in an equation

Answer 32

Question 33

what is the definition of biological half life?

Answer 33

Biological Half-life is defined as the period of time required to reduce the amount of a drug in an organ or the body to exactly one half its original value due solely to biological elimination. tbiol is affected by many external factors. Perhaps the two most important are hepatic and renal function

Question 34

what is the effective half life? and how is it calculated?

Answer 34

A combination of nuclear and biological half lives to capture the effect of both. Effective Half-Life is defined as the period of time required to reduce the radioactivity level of an internal organ or of the whole body to exactly one half its original value due to both elimination and decay. The teff can be measured directly. For example, one can hold a detection device 1 m from the patient’s chest and count the patient multiple times until the reading decreases to half of the initial reading. The patient is permitted to use the rest room between readings as needed, so both elimination and decay are taking place.

Question 35

Q: Which of the following statements best describes the difference between molecular excitation and ionization?​ A. Molecular excitation occurs when an atom or molecule loses an electron, while ionization occurs when an electron transitions to a higher energy level without being removed.​ B. Molecular excitation involves the removal of an electron, while ionization involves the absorption of energy by the nucleus.​ C. Molecular excitation involves an electron moving to a higher energy level within the atom or molecule, while ionization involves the removal of an electron, leaving the atom or molecule positively charged.​ D. Molecular excitation and ionization are identical processes, both involving the removal of electrons from atoms or molecules.​

Answer 35

C

Question 36

Q: In the context of veterinary medicine, which of the following statements best differentiates particulate radiation from electromagnetic radiation?​ A. Particulate radiation travels at the speed of light, while electromagnetic radiation is slower and cannot penetrate biological tissues.​ B. Particulate radiation consists of charged or uncharged particles that have mass, while electromagnetic radiation consists of massless energy waves such as X-rays and gamma rays.​ C. Particulate radiation includes X-rays and gamma rays, while electromagnetic radiation includes alpha and beta particles.​ D. Electromagnetic radiation requires a medium to travel through, while particulate radiation can only exist in a vacuum.​

Answer 36

B

Question 37

Q: What is the best definition of Linear Energy Transfer (LET) in the context of radiation?​ A. The total amount of radiation energy absorbed by an entire organism.​ B. The rate at which ionizing radiation deposits energy in a material per unit distance traveled.​ C. The energy required to completely ionize a molecule or atom in a biological tissue.​ D. The distance radiation travels in a medium before losing all its energy.​

Answer 37

B

Question 38

Q: Which of the following statements correctly describes the basic forms of particulate radiation and their interactions with matter?​ A. Alpha particles are highly ionizing but have low penetration, electrons (beta particles) have moderate ionization and penetration, protons have high ionization potential, and neutrons interact primarily through nuclear collisions.​ B. Alpha particles penetrate deeply into tissues, electrons (beta particles) produce minimal ionization, protons have negligible biological effects, and neutrons primarily ionize water molecules.​ C. Alpha particles are weakly ionizing and only interact with non-biological materials, electrons (beta particles) interact exclusively with metals, protons do not interact with biological matter, and neutrons cause widespread ionization.​ D. Alpha particles and neutrons both produce high penetration and low ionization, while electrons (beta particles) and protons interact exclusively with dense tissues.​

Answer 38

A

Question 39

Q: Which of the following best describes the differences between direct and indirect forms of ionizing radiation and their actions?​ A. Direct ionizing radiation creates free radicals to cause damage, while indirect ionizing radiation directly targets and ionizes DNA molecules.​ B. Direct ionizing radiation involves the interaction of neutral particles, while indirect ionizing radiation involves charged particles.​ C. Both direct and indirect ionizing radiation directly damage cellular membranes, but indirect radiation cannot damage DNA.​ D. Direct ionizing radiation directly ionizes biological molecules, such as DNA, while indirect ionizing radiation primarily generates free radicals through the radiolysis of water, which then damage biomolecules.​

Answer 39

D

Question 40

Q: How does free radical production due to radiation exposure affect biological systems?​ A. Free radicals produced by radiation primarily strengthen DNA bonds, reducing the likelihood of mutations.​ B. Free radicals formed through the radiolysis of water interact with biomolecules, causing oxidative damage to DNA, proteins, and lipids, potentially leading to mutations and cell death.​ C. Free radicals produced by radiation only affect rapidly dividing cells and have no impact on non-dividing tissues.​ D. Free radicals produced during radiation exposure are harmless as long as they remain inside water molecules.​ ​

Answer 40

B

Question 41

1. Which statement best describes the photoelectric effect?​ A photon transfers only a fraction of its energy to an electron, with the remainder scattered as a lower-energy photon.​ B. A photon is elastically scattered, and no electron is ejected.​ C. A photon’s entire energy is transferred to an electron; part of that energy overcomes the electron’s binding energy, and the rest becomes the electron’s kinetic energy.​ D. A photon’s energy converts into two electrons.​

Answer 41

C. A photon’s entire energy is transferred to an electron; part of that energy overcomes the electron’s binding energy, and the rest becomes the electron’s kinetic energy.​ In the photoelectric effect, the incident photon’s entire energy is used to eject the electron; a portion covers the electron’s binding energy, and the remainder is the ejected electron’s kinetic energy.​

Question 42

2. Under which condition can the photoelectric effect occur?​ A. The incident photon energy is less than the electron’s binding energy.​ B. The incident photon energy is exactly equal to the electron’s binding energy.​ C. The incident photon energy must exceed or be equal to the electron’s binding energy.​ D. The photoelectric effect does not depend on the electron’s binding energy.​

Answer 42

C. The incident photon energy must exceed the electron’s binding energy.​ To eject a bound electron, the photon’s energy must be greater than the electron’s binding energy.​ if only equal to, it is technically possible but the electron will have no kinetic energy

Question 43

3. According to the description, if multiple electron shells are available, from which shell is the electron most likely to be ejected?​ A. The outermost shell, because it has the lowest binding energy.​ B. The shell closest to the nucleus for which the photon energy exceeds the binding energy.​ C. Randomly from any shell.​ D. Only from the K-shell, regardless of photon energy.​

Answer 43

B. The shell closest to the nucleus for which the photon energy exceeds the binding energy.​ The electron will be ejected from the highest-energy (most tightly bound) shell that the photon energy can overcome.​

Question 44

4. Why is photoelectric absorption considered beneficial in diagnostic X-ray imaging?​ A. It primarily produces scattered photons, increasing image blur.​ B. It eliminates the need for contrast agents.​ C. It doesn’t generate scattered photons and thus improves image contrast.​ D. It cannot occur with soft tissues, only with metals.​

Answer 44

C. It doesn’t generate scattered photons and thus improves image contrast.​ C – Photoelectric absorption does not produce scattered photons. This increases contrast and detail in diagnostic images.​

Question 45

1. In medical imaging, Compton scattering is the predominant interaction between X‐ray photons and soft tissues over which approximate energy range?​ A. 1–10 keV​ B. 26 keV–30 MeV​ C. 50–150 MeV​ D. Above 1.02 MeV​

Answer 45

B. Compton scattering dominates from roughly 26 keV to 30 MeV. This spans the diagnostic range (tens to hundreds of keV) up to higher gamma energies.​

Question 46

Which factor most strongly influences the probability of Compton scattering in a given material?​ A. Atomic number (Z)​ B. Electron density (electrons per gram)​ C. Photon frequency alone​ D. The K‐edge of the material​

Answer 46

B. The probability of Compton scattering is proportional to electron density, not strongly dependent on atomic number. Since most elements (except hydrogen) have similar electrons/gram, density is the main variable.​

Question 47

Pair production becomes possible when the incident photon energy exceeds approximately:​ A. 26 keV​ B. 150 keV​ C. 1.02 MeV​ D. 10 MeV​

Answer 47

C. Pair production requires at least 1.02 MeV (the combined rest‐mass energy of an electron and positron). Below this threshold, pair production cannot occur.​

Question 48

Photodisintegration refers to a process where a very high‐energy photon is absorbed by the nucleus, causing emission of subatomic particles. Is this interaction relevant in routine diagnostic X‐ray imaging?​ A. Yes, it explains image contrast in mammography.​ B. Yes, it is the main reason for scatter radiation below 50 keV.​ C. No, it only occurs at photon energies well above the diagnostic range.​ D. No, because photodisintegration only happens with free electrons.​

Answer 48

Photodisintegration requires very high gamma‐ray energies (often several MeV or more). It is not relevant in the typical X‐ray diagnostic range (keV), where Compton scattering and photoelectric absorption dominate.​

Question 49

1. Which statement best describes attenuation in the context of a parallel beam of photons passing through matter?​ A. Attenuation only includes absorption, not scattering.​ B. Attenuation includes both absorption and scattering of photons.​ C. Attenuation does not depend on beam geometry.​ D. Attenuation is independent of the incident beam intensity.

Answer 49

B. Attenuation is defined as the reduction in beam intensity due to both absorption and scattering. In a narrow‐beam setup, the measured attenuation is more accurate since scattered photons are less likely to reach the detector.​

Question 50

How does the mass attenuation coefficient (MAC) differ from the linear attenuation coefficient (LAC)?​ A.MAC factors in the density of the material, whereas LAC does not.​ B. LAC is used only for photons above 1 MeV, while MAC is used below 1 MeV.​ C. MAC removes the effect of density, so it remains constant for a given substance regardless of physical state.​ D. Only LAC is valid in diagnostic radiology; MAC is used purely in radiation therapy.​

Answer 50

C. The mass attenuation coefficient (MAC) is the LAC divided by density. This “normalizes” out density effects, making MAC constant for a given material regardless of its physical state (solid, liquid, or gas).​

Question 51

The half‐value layer (HVL) is defined as the thickness of a material required to reduce the beam intensity to half its original value. Which statement correctly describes its relationship with the linear attenuation coefficient (μ)?​ A.HVL and μ are directly proportional.​ B. HVL is equal to μ × density.​ C. HVL and μ are inversely proportional to each other.​ D. HVL is unrelated to μ​

Answer 51

C. HVL = ln(2)/μ, so the half‐value layer (HVL) is inversely proportional to the linear attenuation coefficient.​

Question 52

4. Which statement accurately differentiates absorbed dose, equivalent dose, and effective dose?​ A. Absorbed dose (in Gray) always exceeds equivalent dose (in Sievert).​ B. Equivalent dose = absorbed dose × radiation weighting factor; effective dose = sum of equivalent doses to each organ × tissue weighting factor.​ C. Effective dose and absorbed dose have the same numerical value but different units.​ D. Absorbed dose is measured in Coulombs per kg of air.​

Answer 52

B. Absorbed dose (D) is energy deposited per unit mass (Gray). - Equivalent dose (H)= absorbed dose × radiation weighting factor (Sievert). - Effective dose = sum of equivalent doses to each organ multiplied by each organ’s tissue weighting factor (also in Sievert).​ ​

Question 53

which decay modes mean the mass number stays the same?

Answer 53

isomeric transition, positron emission, electron capture. Beta minus as well

Question 54

how are the number of remaining radioactive atoms and the number of elapsed half lives related in an equation?

Answer 54

Physical half life: T1/2 = The time required for the number of radioactive atoms in a sample to decrease by half. The number of radioactive atoms remaining in the sample and the number of elapsed half lives are related by the following equation: N=N0/2^n Where N is the number of atoms remaining, N0 is the initial number of radioactive atoms, and n is the number of half lives that have elapsed. alternatinvely it can be written as N=N0 (1/2)^n

Question 55

how do you work out the decay constant?

Answer 55

decay constant (lambda)= ln(2)/ T(1/2) ln(2)= 0.693

Question 56

what is planks constant? E=?

Answer 56

Planks constant= 6.62x10-34 J/Hz E=hf Therefore energy is proportional to frequency. Ch= Eλ

Question 57

what is the wavelength of diagnostic xr?

Answer 57

10^-8 to 10^-11 metres or 0.01nm- 10nm

Question 58

Which phases of the cell cycle is most susceptible to radiation treatment? (2) a) S phase b) G1 c) Late G2 d) Early G2 e) D phase f) M phase

Answer 58

Late G2 and M phase G2- post DNA synthesis, pre-mitosis * preparation for division M- mitosis

Question 59

Which phases of the cell cycle is LEAST susceptible to radiation treatment? a) S phase b) G1 c) Late G2 d) Early G2 e) D phase f) M phase

Answer 59

s- synthesis

Question 60

what type of cell death occurs most commonly after radiation treatment of solid tumours? what time in the cell cycle does it occur?

Answer 60

mitotic cell death, during mitosis Mitosis and G2 phase most sensitive to radiation Hematopoietic and lymphoid cells- apoptosis- during interhase