Physics (AS & A Level) · May / June 2026 · Paper 14 · Question 39

An unstable nucleus ^{11}_{6}C decays in a single step to form a stable nucleus. During the decay, a nucleon of the unstable nucleus is changed when an up quark in the nucleon becomes a down quark. What is the stable nucleus that is formed?

1. A^{11}_{5}B
2. B^{11}_{7}N
3. C^{12}_{6}C
4. D^{10}_{6}C

As printed in the paper