Properties of α, β, γ radiations MCQs With Answer

Properties of α, β, γ radiations MCQs With Answer
This concise guide covers the fundamental properties of alpha, beta and gamma radiations—mass, charge, penetrating and ionizing power, interactions with matter, shielding, detectors, biological effects, and applications in pharmacy. Tailored for B. Pharm students, the content emphasizes practical concepts such as LET, RBE, decay modes, units (Bq, Ci, Gy, Sv), and common isotopes used in radiolabeling, sterilization and imaging. Clear comparisons and real-world relevance help you master radiation safety and dosimetry principles critical in pharmaceutical practice. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which of the following radiations has the greatest mass?

• Alpha particle (helium nucleus)
• Beta particle (electron)
• Gamma photon
• Positron

Correct Answer: Alpha particle (helium nucleus)

Q2. What is the typical electric charge of an alpha particle?

• +2 elementary charges
• +1 elementary charge
• 0 (neutral)
• -1 elementary charge

Correct Answer: +2 elementary charges

Q3. Which radiation has the highest penetrating power in matter?

• Alpha radiation
• Beta radiation
• Gamma radiation
• Neutron radiation

Correct Answer: Gamma radiation

Q4. Which radiation has the highest ionizing power per unit path length?

• Alpha radiation
• Beta radiation
• Gamma radiation
• X-rays

Correct Answer: Alpha radiation

Q5. Which radiation typically travels only a few centimeters in air?

• Alpha radiation
• High-energy gamma radiation
• High-energy beta radiation
• Neutron radiation

Correct Answer: Alpha radiation

Q6. Which material is generally sufficient to stop alpha particles?

• Paper or a few centimeters of air
• 1 cm of aluminum
• 10 cm of lead
• 1 mm of steel

Correct Answer: Paper or a few centimeters of air

Q7. Which shielding is most appropriate to reduce beta radiation while minimizing bremsstrahlung?

• Low-Z material such as plastic or acrylic
• Lead shielding of 1 cm thickness
• High-Z material like tungsten
• Concrete only

Correct Answer: Low-Z material such as plastic or acrylic

Q8. Which shielding material is commonly used to attenuate gamma radiation?

• Lead
• Plastic
• Thin paper
• Air gap

Correct Answer: Lead

Q9. Which charged radiation will be deflected toward the negative plate in an electric field?

• Alpha particles
• Beta-minus electrons
• Gamma photons
• Neutrons

Correct Answer: Alpha particles

Q10. Positron emission (beta plus) results in which immediate secondary event useful in medical imaging?

• Two 511 keV annihilation photons emitted approximately 180° apart
• Emission of a high-energy alpha particle
• Production of bremsstrahlung X-rays only
• Direct gamma emission at 1 keV

Correct Answer: Two 511 keV annihilation photons emitted approximately 180° apart

Q11. What is the SI unit of radioactivity?

• Becquerel (Bq)
• Gray (Gy)
• Sievert (Sv)
• Curie (Ci)

Correct Answer: Becquerel (Bq)

Q12. Which radiation has the highest Linear Energy Transfer (LET)?

• Alpha radiation
• Beta radiation
• Gamma radiation
• Ultraviolet radiation

Correct Answer: Alpha radiation

Q13. Which radiation type typically has the greatest relative biological effectiveness (RBE) for causing cellular damage?

• Alpha particles
• Beta particles
• Gamma rays
• Visible light

Correct Answer: Alpha particles

Q14. In the energy range ~100 keV to several MeV, which interaction is dominant for gamma photons in soft tissue?

• Compton scattering
• Pair production
• Photoelectric absorption
• Elastic scattering without energy transfer

Correct Answer: Compton scattering

Q15. At low gamma photon energies and high atomic number absorbers, which process dominates photon attenuation?

• Photoelectric effect
• Compton scattering
• Pair production
• Neutron capture

Correct Answer: Photoelectric effect

Q16. Pair production by a photon requires a minimum photon energy of approximately:

• 1.022 MeV
• 0.511 MeV
• 10 keV
• 100 eV

Correct Answer: 1.022 MeV

Q17. An alpha particle is composed of which combination of nucleons?

• 2 protons and 2 neutrons
• 1 proton and 1 neutron
• 2 protons and 1 neutron
• 3 neutrons

Correct Answer: 2 protons and 2 neutrons

Q18. In beta-minus decay, which particle is emitted along with the electron?

• Antineutrino
• Neutrino
• Positron
• Alpha particle

Correct Answer: Antineutrino

Q19. Which detector material is commonly used for sensitive alpha particle detection in lab studies?

• ZnS(Ag) scintillation detector
• Geiger-Müller tube with thin window for gamma only
• NaI(Tl) scintillator for low-energy electrons only
• Cloud chamber for gamma spectroscopy

Correct Answer: ZnS(Ag) scintillation detector

Q20. Which radiation detection device typically gives count rates but no accurate energy spectrum?

• Geiger-Müller counter
• High-purity germanium (HPGe) detector
• Scintillation spectrometer with PMT
• Semiconductor spectroscopy detector

Correct Answer: Geiger-Müller counter

Q21. The half-life of a radionuclide is defined as:

• The time required for half of the radioactive nuclei to decay
• The time for activity to drop to zero
• The time for a single nucleus to decay
• The time for the emitted radiation to travel one meter

Correct Answer: The time required for half of the radioactive nuclei to decay

Q22. Which radiation source is widely used for sterilization of pharmaceutical products?

• Cobalt-60 gamma rays
• Alpha emitters like Po-210
• Low-energy UV lamps only
• Beta emitters that cannot penetrate packaging

Correct Answer: Cobalt-60 gamma rays

Q23. Which radionuclide is frequently used for radiolabeling organic molecules in pharmacokinetic studies?

• Carbon-14
• Uranium-238
• Cobalt-60
• Americium-241

Correct Answer: Carbon-14

Q24. Which positron-emitting isotope is commonly used in PET imaging?

• Fluorine-18
• Cobalt-60
• Carbon-14
• Phosphorus-32

Correct Answer: Fluorine-18

Q25. Linear Energy Transfer (LET) is defined as:

• Energy deposited per unit path length by a charged particle
• Number of decays per second
• Probability of photon scattering
• Half-life divided by activity

Correct Answer: Energy deposited per unit path length by a charged particle

Q26. The Bragg peak is a feature of which type of radiation?

• Charged particles (e.g., protons, alpha particles)
• Gamma rays
• Neutrons
• Infrared radiation

Correct Answer: Charged particles (e.g., protons, alpha particles)

Q27. Beta decay is always accompanied by the emission of which almost massless neutral particle or antiparticle?

• Neutrino or antineutrino
• Photon
• Neutron
• Proton

Correct Answer: Neutrino or antineutrino

Q28. Which radiation has the shortest penetration depth in biological tissue?

• Alpha radiation
• Beta radiation
• Gamma radiation
• Neutron radiation

Correct Answer: Alpha radiation

Q29. Which radiation interaction generates bremsstrahlung when decelerated in a high-Z absorber?

• Beta electrons (charged particles)
• Alpha particles only
• Gamma photons directly
• Neutrons

Correct Answer: Beta electrons (charged particles)

Q30. To minimize bremsstrahlung production when shielding beta emitters, which material is preferred?

• Plastic or acrylic (low-Z)
• Thick lead shielding
• High-Z metal like tungsten
• Pure copper of high density

Correct Answer: Plastic or acrylic (low-Z)

Q31. Which statement about gamma photons is correct?

• They have no rest mass and no electric charge
• They consist of two protons and two neutrons
• They carry a positive electric charge
• They are identical to beta particles

Correct Answer: They have no rest mass and no electric charge

Q32. Gamma radiation primarily ionizes matter by:

• Producing energetic secondary electrons that cause ionization
• Directly knocking out protons from nuclei
• Transferring charge like charged particles
• Creating chemical bonds

Correct Answer: Producing energetic secondary electrons that cause ionization

Q33. What is the conversion factor from curie to becquerel?

• 1 Ci = 3.7 × 10^10 Bq
• 1 Ci = 1 Bq
• 1 Ci = 100 Bq
• 1 Ci = 3.7 × 10^-10 Bq

Correct Answer: 1 Ci = 3.7 × 10^10 Bq

Q34. Which unit describes absorbed dose of radiation in terms of energy deposited per unit mass?

• Gray (Gy)
• Becquerel (Bq)
• Curie (Ci)
• Sievert (Sv)

Correct Answer: Gray (Gy)

Q35. Which unit accounts for biological effect by weighting absorbed dose?

• Sievert (Sv)
• Gray (Gy)
• Becquerel (Bq)
• Curie (Ci)

Correct Answer: Sievert (Sv)

Q36. Emission of an alpha particle from a nucleus changes the mass number by:

• Decrease by 4
• Decrease by 1
• Increase by 4
• No change

Correct Answer: Decrease by 4

Q37. In beta-plus decay (positron emission), a proton in the nucleus converts into:

• A neutron
• A proton plus electron
• An alpha particle
• A neutrino only

Correct Answer: A neutron

Q38. Which radiation is most strongly deflected by a magnetic field?

• Beta particles (electrons) due to high charge-to-mass ratio
• Alpha particles due to larger mass
• Gamma photons because they are neutral
• Neutrons because they are neutral

Correct Answer: Beta particles (electrons) due to high charge-to-mass ratio

Q39. Characteristic X-rays are produced primarily by which process following nuclear decay?

• Inner-shell electron vacancies leading to atomic electron transitions
• Direct emission of alpha particles
• Neutron capture exclusively
• Positron annihilation only

Correct Answer: Inner-shell electron vacancies leading to atomic electron transitions

Q40. Stopping power of a medium for a charged particle generally increases with:

• Particle charge and decreasing particle velocity
• Increasing photon energy
• Lower atomic number of absorber only
• Distance from source only

Correct Answer: Particle charge and decreasing particle velocity

Q41. Which detector is best suited for high-resolution gamma spectroscopy in a research lab?

• High-purity germanium (HPGe) detector
• Geiger-Müller counter
• Simple NaCl crystal
• ZnS(Ag) alpha probe

Correct Answer: High-purity germanium (HPGe) detector

Q42. Emission of an alpha particle from element Z will produce an element with atomic number:

• Z – 2
• Z + 2
• Z – 1
• Unchanged Z

Correct Answer: Z – 2

Q43. Which type of radiation is most likely to induce DNA double-strand breaks per unit dose?

• Alpha particles (high LET)
• Low-energy beta particles
• Low-energy photons only
• Visible light

Correct Answer: Alpha particles (high LET)

Q44. Positron annihilation produces gamma photons of what energy each?

• 511 keV
• 1.022 keV
• 100 keV
• 10 eV

Correct Answer: 511 keV

Q45. Which practice reduces biological damage from an external radiation source?

• Reducing dose rate and exposure time
• Increasing time of exposure
• Removing shielding
• Holding source closer to body

Correct Answer: Reducing dose rate and exposure time

Q46. The practical range of therapeutic beta particles in tissue is typically:

• A few millimeters to several centimeters depending on energy
• Several meters
• Micrometers only
• Unlimited

Correct Answer: A few millimeters to several centimeters depending on energy

Q47. Which isotope is commonly used as a gamma source for industrial and medical sterilization?

• Cobalt-60
• Uranium-235
• Carbon-14
• Phosphorus-32

Correct Answer: Cobalt-60

Q48. For non-contact thickness gauging of thin pharmaceutical films, which radiation is commonly used?

• Beta particles
• Alpha particles
• Gamma rays always preferred
• Visible light only

Correct Answer: Beta particles

Q49. When a gamma photon ejects an inner-shell electron, the emitted electron is called a:

• Photoelectron
• Alpha particle
• Neutrino
• Positron

Correct Answer: Photoelectron

Q50. Which safety precaution is essential when working with unsealed radioactive sources in a pharmacy lab?

• Use designated containment (fume hood or glove box), shielding, monitoring and strict contamination control
• Store sources on bench tops without labeling
• Allow open handling without gloves to feel the source
• Rely solely on distance without monitoring instruments

Correct Answer: Use designated containment (fume hood or glove box), shielding, monitoring and strict contamination control

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com