A computer model gives these results for two successive emissions, X and Y, from an unstable nucleus.
| Stage | Number of protons | Number of neutrons | Energy above the lowest energy arrangement / keV |
|---|---|---|---|
| before emission X | 29 | 36 | not recorded |
| after emission X and before emission Y | 30 | 35 | 780 |
| after emission Y | 30 | 35 | 120 |
A student concludes that emission X was beta-plus radiation and emission Y was gamma radiation.
Evaluate the student's conclusion.