Introduction
- Radiation Physics—On hearing the name, people either get danger signs or remember the X-ray machine! But in reality, radiation physics is a fascinating world where there is a deep interaction between energy and matter—which not only helps us in diagnosing but also helps in treating diseases like cancer, generating electricity, and even exploring space.
- This subject tells how alpha, beta, gamma, X-rays, and neutron radiations travel inside matter, transfer energy, and how they are controlled or detected. Radiation physics is that powerful tool of science that has power as well as responsibility—especially when it comes to safety!
- In this series we will understand their questions, answers, and explanations step by step: Like
- Types of radiation
- Interaction of radiation with matter
- Detection & measurement techniques
- Radiation units, shielding, safety protocols And real-world applications
Que1: The best source used for soil density measurement.
a) n b) beta c) gamma d) alpha
Answer: c) gamma
Explanation: Gamma rays are used to measure soil density because they have high penetration power and can penetrate deep into the soil. This technique is called the gamma attenuation method.
Que2: The imported source is to be sent for disposal.
a) BRIT b) Origin country from which were exported
c) AERB d) User
Answer: b) Origin country from which were exported
Explanation: According to international regulation, radioactive sources have to be disposed of in the same country from where they were originally exported. This is for safety and accountability.
Explanation: According to international regulation, radioactive sources have to be disposed of in the same country from where they were originally exported. This is for safety and accountability.
Que3: For neutron source shielding, which material is used?
a) plastics b) paper c) steel d) paraffin wax
Answer: d) paraffin wax
Explanation: Paraffin wax is a simple, cost-effective neutron moderator. Hydrogen-rich materials such as paraffin wax are used to shield neutrons. It is very effective in slowing down neutrons.
Explanation: Paraffin wax is a simple, cost-effective neutron moderator. Hydrogen-rich materials such as paraffin wax are used to shield neutrons. It is very effective in slowing down neutrons.
Que4: For beta source shielding, which material is used?
a) plastics b) paper c) steel d) paraffin wax
Answer: a) plastics
Explanation: Beta particles have less penetrative power compared to gamma rays; hence, light material like plastic is enough to stop them.
Que5: Iridium 192 has a radiation level of 4 mR/h for 2 meters. What will be at 1 meter?
a) 8 mR/h b) 16 mR/h c) 4 mR/h d) 2 mR/h
Answer: b) 16 mR/h
Explanation: According to the inverse square law, the intensity becomes 4 times when the distance is half.
Que6: TVT is equal.
a) 3.33 HVT b) 1 HVT c) 2.22 HVT d) 3 HVT
Answer: a) 3.33 HVT
Explanation:
1 TVT (Tenth Value Thickness) = 3.33 Half Value Thickness (HVT).
TVT is the thickness where radiation becomes 1/10th, whereas in HVT it is 1/2.
Explanation:
1 TVT (Tenth Value Thickness) = 3.33 Half Value Thickness (HVT).
TVT is the thickness where radiation becomes 1/10th, whereas in HVT it is 1/2.
Que7: Sievert is a unit of?
a) Activity b) exposure c) Dose d) effective dose
Answer: d) effective dose
Explanation:
Sievert (Sv) measures the biological effects of radiation. This is the product of dose and radiation weighting factor.
Explanation:
Sievert (Sv) measures the biological effects of radiation. This is the product of dose and radiation weighting factor.
Que8: Which department is issuing the RSO certificate?
a) AERB b) BRIT c) RP&AD d) All of above
Answer: a) AERB
Explanation:
The Radiation Safety Officer (RSO) certificate is issued by AERB (Atomic Energy Regulatory Board), which is the regulator of radiation sources in India.
Explanation:
The Radiation Safety Officer (RSO) certificate is issued by AERB (Atomic Energy Regulatory Board), which is the regulator of radiation sources in India.
Que9: What is one who is issued the license known as?
a) AERB b) BRIT c) RP&AD d) Licensee
Answer: d) Licensee
Explanation:
The person or institute in whose name the license for a radiation source is issued is called the licensee.
Explanation:
The person or institute in whose name the license for a radiation source is issued is called the licensee.
Que10: Nucleonic gauge installation, service and maintenance, disposal, and return to service are done by whom?
a) AERB b) BRIT c) RSO d) Manufacturer and vendor
Answer: d) Manufacturer and vendor
Explanation:
This work can only be done by authorized manufacturers and vendors as per the norms for safety and compliance.
Explanation:
This work can only be done by authorized manufacturers and vendors as per the norms for safety and compliance.
Que11: What are the license rules numbered as per the AERB Act?
a) Rule no. 33 b) Rule no. 35 c) Rule no. 20 d) Rule no. 19
Answer: a) Rule no. 33
Explanation: The license of ARAB related to the radiation source comes under Rule No. 33.
Que12: From 80 mR/h to 40 mR/h, how many TVT and HVT can be used?
a) 1 TVT + 3 HVT
b) 3 TVT + 1 HVT
c) 2 TVT +2 HVT
d) 3 TVT + 2 HVT
Answer: a) 1 TVT + 3 HVT
Que13: What will be the reduction factor for 2 TVT and 1 HVT?
a) 100 b) 300 c) 400 d) 200
Answer: d) 200
Explanation:
1 TVT = 1/10
2 TVT = 1/100
1 HVT = 1/2
Total = (1/100) × (1/2) = 1/200
2 TVT = 1/100
1 HVT = 1/2
Total = (1/100) × (1/2) = 1/200
Reduction factor = 200
Que14: Production of bremsstrahlung radiation is high in
a) Plastics b) copper c) lead d) all of above
Answer: c) lead
Explanation: When a high-energy particle collides with a material having a high atomic number (z), we get bremsstrahlung radiation, which is directly dependent on the atomic number (z).
Bremsstrahlung ∝ Z² (atomic number squared)
Bremsstrahlung ∝ Z² (atomic number squared)
Que15: Example if nonionizing radiation is
a) x-ray b) gamma c) ultraviolet ray d) all of these
Answer: c) ultraviolet ray
Explanation:
Ionizing Radiation: Which can remove electrons from atoms (cause ionization)—such as X-rays, gamma rays, alpha, and beta.
Non-ionizing radiation: Which does not ionize but can excite or vibrate atoms/molecules.
Que16: When an electron is emitted from a radioactive source, the atomic mass of the radioactive source degrades.
a) reduces by 1 b) same c) increase by 1 d) reduces by 2
Answer: b) same
Que17: On 1st Jan 2023, the activity of a co-60 source is 37 GBq; what will be its activity?
On 1st March 2028?
a) 18.5 GBq b) 18.5 MBq c) 1.85 GBq d) 1.85 MBq
Answer: a) 18.5 GBq
Explanation:
Half-life of Co-60 = ~5.27 years
Time = ~5.17 years ≈ 1 half-life
So activity becomes half: 37 / 2 = 18.5 GBq
Explanation:
Half-life of Co-60 = ~5.27 years
Time = ~5.17 years ≈ 1 half-life
So activity becomes half: 37 / 2 = 18.5 GBq
Que18: Compton scattering involves.
a) free electron b) bound electron c) nucleus d) positron
Answer: a) free electron
Explanation:
Compton scattering occurs when a photon collides with a loosely bound or free electron. Some part of the energy is given to the electron.
Explanation:
Compton scattering occurs when a photon collides with a loosely bound or free electron. Some part of the energy is given to the electron.
Que19: 1 mGy is equal to how much mR?
a) 100 mR b) 1 mR c) 1000 mR d) 10 mR
Answer: a) 100 mR
Explanation:
1 Gray = 100 rad
1 mGy = 0.1 rad
1 rad = 1000 mR
So, 0.1 rad = 100 mR
Explanation:
1 Gray = 100 rad
1 mGy = 0.1 rad
1 rad = 1000 mR
So, 0.1 rad = 100 mR
Que20: The radiation weighting factor depends upon which of the following.
a) Energy of radiation b) Type of radiation
b) Half life d) all of the above
Answer: b) Type of radiation
Explanation:
Radiation weighting factor depends on the type of radiation (e.g., alpha, beta, gamma). Alpha factor is higher because biological damage is also higher
Explanation:
Radiation weighting factor depends on the type of radiation (e.g., alpha, beta, gamma). Alpha factor is higher because biological damage is also higher
Note :
