Nuclear Physics Practice Questions
A-Levels · A-Level Physics · 141 free MCQs with instant results and detailed explanations.
141
Total
41
Easy
78
Medium
22
Hard
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Sample Questions from Nuclear Physics
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Q1
Easy
Which type of radiation consists of high-energy electromagnetic waves and is often emitted during radioactive decay?
A.
Alpha particles
B.
Beta particles
C.
Gamma rays
D.
Neutrons
Show Answer & Explanation
Correct Answer: C
Gamma rays are high-energy electromagnetic waves emitted during radioactive decay. Unlike alpha and beta particles, which are charged, gamma rays are neutral and have no mass.
Q2
Easy
If a radioactive isotope has a half-life of 10 years, how much of a 100g sample will remain after 30 years?
A.
12.5g
B.
25g
C.
50g
D.
75g
Show Answer & Explanation
Correct Answer: A
After 30 years, which is three half-lives (10 years each), the remaining amount of the sample can be calculated as: 100g -> 50g (after 10 years) -> 25g (after 20 years) -> 12.5g (after 30 years).
Q3
Easy
What is the primary purpose of a moderator in a nuclear reactor?
A.
To absorb neutrons
B.
To slow down neutrons
C.
To increase the temperature
D.
To generate steam
Show Answer & Explanation
Correct Answer: B
The primary purpose of a moderator in a nuclear reactor is to slow down fast neutrons produced during fission, enabling them to effectively sustain the chain reaction by increasing the probability of further fission.
Q4
Medium
What is the process called when a nucleus emits an alpha particle?
A.
Alpha decay
B.
Beta decay
C.
Gamma decay
D.
Fission
Show Answer & Explanation
Correct Answer: A
Alpha decay is the process where a nucleus emits an alpha particle, which consists of 2 protons and 2 neutrons, resulting in a new nucleus.
Q5
Medium
In nuclear fission, what is typically used to initiate the reaction?
A.
Gamma rays
B.
Fast neutrons
C.
Alpha particles
D.
Beta particles
Show Answer & Explanation
Correct Answer: B
Fast neutrons are used to initiate nuclear fission by colliding with heavy nuclei, causing them to split and release energy.
Q6
Medium
If the half-life of a radioactive substance is 10 years, how much of a 100 g sample remains after 30 years?
A.
12.5 g
B.
25 g
C.
50 g
D.
75 g
Show Answer & Explanation
Correct Answer: A
After 30 years (3 half-lives), the remaining mass is 100 g / 2^3 = 12.5 g.
Q7
Medium
Which type of radiation is most penetrating and requires a thick lead shield to stop it?
A.
Alpha radiation
B.
Beta radiation
C.
Gamma radiation
D.
Neutron radiation
Show Answer & Explanation
Correct Answer: C
Gamma radiation is highly penetrating and can pass through most materials, requiring dense materials like lead for effective shielding.
Q8
Hard
In a nuclear reactor, the fission of U-235 produces neutrons along with fission fragments. If a reactor is designed to sustain a chain reaction, what is the term used to describe the minimum amount of fissile material required to maintain that reaction?
A.
Critical mass
B.
Mass defect
C.
Fission cross-section
D.
Thermal neutron flux
Show Answer & Explanation
Correct Answer: A
Critical mass is the minimum quantity of fissile material needed to maintain a nuclear chain reaction. Below this mass, the reaction cannot sustain itself due to insufficient neutron production.
Q9
Hard
A radioactive substance has a half-life of 10 years. If you start with 80 grams of this substance, how much will remain after 30 years?
A.
10 grams
B.
20 grams
C.
40 grams
D.
5 grams
Show Answer & Explanation
Correct Answer: A
After 30 years (which is three half-lives), the remaining mass will be 80g / 2^3 = 80g / 8 = 10g.
Q10
Hard
In a nuclear reaction, a neutron collides with a Uranium-235 nucleus causing it to fission. If 3 neutrons are released in the process, which of the following statements is true regarding the reaction?
A.
It is a spontaneous reaction without external energy.
B.
It releases energy that can be harnessed for power generation.
C.
Only one neutron is released from the reaction.
D.
The resulting nucleus is always barium-144.
Show Answer & Explanation
Correct Answer: B
The fission of Uranium-235 releases a significant amount of energy, which can be harnessed for power generation, while also producing multiple neutrons.
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Practice All 141 Questions →Nuclear Physics — A-Levels A-Level Physics Practice Questions Online
This page contains 141 practice MCQs for the chapter Nuclear Physics in A-Levels A-Level Physics. The questions are organized by difficulty — 41 easy, 78 medium, 22 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.