AQA A-Level Physics Paper 1, November 2020: Question 9
1 mark · Easy difficulty · Multiple Choice
Identify particle X in the nuclear fusion equation between a deuterium nucleus and a tritium nucleus.
Practise this questionQuestion
Question text
09 A deuterium nucleus and a tritium nucleus fuse together to produce a helium nucleus and
particle X.
2H + 3H → 4He + X
11 2
What is X?
[1 mark]
A an electron
B a neutron
C a positron
D a proton
Mark scheme
Show the mark scheme
09 B
How to answer it
Identifying Particles in Nuclear Fusion
What this question tests
This question assesses your ability to balance nuclear equations by conserving nucleon number (top number) and proton number (bottom number). It tests fundamental knowledge of particle physics notation and nuclear fusion reactions.
Determining Particle X
✅ Correct Answer
B (a neutron)
💡 Key Knowledge
- Nucleon Conservation: Total mass numbers (superscripts) on the left must equal the total on the right.
- Proton Conservation: Total atomic numbers (subscripts) on the left must equal the total on the right.
- Neutron notation: ¹₀n (mass number 1, charge/proton number 0).
🧠 Exam Technique
Set up simple mathematical equations using the given isotope symbols:
- Mass numbers: 2 + 3 = 4 + Amass → Amass = 1
- Proton numbers: 1 + 1 = 2 + Zproton → Zproton = 0
- Match your values (1, 0) to a neutron ( ¹₀n ).
❌ Common Errors
Some students miscalculate by incorrectly adding the subscript numbers instead of treating superscripts and subscripts separately, or confuse a proton ( ¹₁p ) with a neutron due to careless arithmetic with the bottom numbers.
Topics
Physics · 3.2 Particles and radiation
Question and mark scheme from the AQA A-Level Physics examination, Paper 1, November 2020. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.