Question

1. according to the generalized nucleosynthesis in a massive star diagram, which of the following stellar fusion stages has the shortest duration? (1) helium fusing into carbon (2) hydrogen fusing into helium (3) carbon fusing into oxygen (4) silicon fusing into iron

Explanation:

In massive stars, as the fusion stages progress, each subsequent stage becomes shorter - lived. Hydrogen - to - helium fusion is the longest - lived (main - sequence phase). Helium - to - carbon is shorter than hydrogen - to - helium. Carbon - to - oxygen is shorter than helium - to - carbon. Silicon - to - iron fusion is the shortest among these as it occurs very rapidly near the end of the star's life before a supernova explosion.

Answer:

(4) silicon fusing into iron