Question 1:

For a medical tracer, the radiation must be able to escape the body to be detected by external cameras.

• Alpha: Stopped by skin or a few cm of air — cannot escape the body.

• Beta: Can travel through tissue, but is often stopped within a few mm to cm, depending on energy.

• Gamma: Highly penetrating — passes easily through body tissues and can be detected externally.

So the type of radiation that passes most easily through body tissues is gamma.

Answer: C

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 2:

For a medical tracer, the half-life needs to balance two things:

1. Long enough to take pictures (at least minutes to hours)

2. Short enough to minimize patient radiation dose (decays away quickly after imaging)

• A few years ❌ — too long, patient would be exposed for years.

• A few hours ✅ — ideal. Long enough to image, short enough to decay within a day.

• A few seconds ❌ — too short; tracer would decay before imaging is complete.

• A few months ❌ — too long; unnecessary prolonged exposure.

So the most realistic half-life is a few hours.

Answer: B

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 3:

The fuel source for a nuclear power station is typically Uranium (specifically Uranium-235 or Plutonium-239 in some reactors).

• Hydrogen ❌ (used in fusion, not current fission power stations)

• Lead ❌ (used for shielding, not fuel)

• Uranium ✅ (fissile isotope U-235 is the main fuel)

• Potassium ❌ (not a nuclear fuel)

Answer: C

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 4:

The process of splitting atoms to release energy is called nuclear fission.

• Nuclear fission ✅ — splitting heavy nuclei (like uranium) into smaller nuclei, releasing energy.

• Nuclear fusion ❌ — combining light nuclei (like hydrogen) into heavier nuclei.

• Atomic breakdown ❌ — not a standard term for this process.

• Thermal splitting ❌ — not correct.

Answer: A

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 5:

In nuclear fission, the particle that hits the nuclear fuel atoms (like Uranium-235) to start the process is a neutron.

• Alpha ❌ — alpha particles are too large and charged; they don’t initiate fission efficiently.

• Electrons ❌ — electrons don’t cause fission of heavy nuclei.

• Neutrons ✅ — uncharged, so they can penetrate the nucleus easily and trigger fission.

• Protons ❌ — charged, repelled by the positive nucleus, not used to start fission in reactors.

Answer: C

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 6:

When each fission releases neutrons that go on to split more fuel atoms, causing a self-sustaining series of fissions, this process is called a chain reaction.

• Chain reaction ✅ — correct term for this process.

• Cascade reaction ❌ — not the standard term in nuclear physics.

• Avalanche reaction ❌ — used in other contexts (e.g., electrical breakdown), not nuclear fission.

• Nuclear multiplier reaction ❌ — not correct.

Answer: A

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 7:

When the nucleus splits, the fission products (smaller nuclei, neutrons, gamma rays) are moving very fast — they have kinetic energy.

This kinetic energy is then converted into thermal energy (heat) as the particles collide with surrounding material in the reactor.

The question asks: "What form/store of energy do all the products of this reaction have?" — meaning immediately after fission, before they interact with anything else.

That is kinetic energy.

• Kinetic energy ✅ — all products are in motion.

• Thermal energy ❌ — that comes later when kinetic energy is transferred.

• Chemical energy ❌ — not relevant to nuclear fission.

• Elastic energy ❌ — not relevant.

Answer: B

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 8:

In a nuclear reactor, the green rods shown are control rods.

• Function: They absorb neutrons to control the reaction rate.

• When lifted (removed from the core), fewer neutrons are absorbed, so more neutrons are available to cause fission, and the reaction rate increases.

• When lowered, they absorb more neutrons and slow/stop the reaction.

Moderators (like water or graphite) slow down neutrons, but they are not the green rods — that's a different component.

So:

• Name: control rod

• Function: absorb neutrons

That matches option C.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 9:

For measuring thickness of aluminium foil:

• Alpha ❌ — too easily stopped; cannot penetrate even thin foil.

• Beta ✅ — ideal. Beta particles have medium penetration. The amount passing through the foil depends on foil thickness. Thin foil allows some beta through; thicker foil stops more.

• Gamma ❌ — too penetrating; would pass through even thick foil with little change, so not sensitive to small thickness variations.

• All three ❌ — only beta works well for this thickness range.

Answer: B

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 10:

Let's reason through this:

• If the half-life is too short, the source decays quickly. The detector will see a falling count rate over time (even if foil thickness is constant), interpret it as the foil getting thicker, even though it is not. The automated system will then try to correct this by making the rollers closer together — making the foil thinner.

• If the half-life is long (e.g., years), the source activity remains nearly constant, so changes in detector reading reflect actual thickness changes, not decay.

So:

• Suitable half-life: long (so no unnecessary adjustments)

• Wrong half-life (short): foil eventually made too thin

That matches option D.

*A.I. got this one wrong and needed correcting.
The silverback

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.