Which of these reactions is responsible for energy radiating from stars, including the sun? a) nuclear fusion b) nuclear fission c) an exothermic chemical reaction d) an endothermic chemical reaction

A) Nuclear fusion

Explanation:

Nuclear fusion is a process that occurs when two light nuclei fuse together forming a heavier nucleus. In such a process, the mass of the final nucleus is slightly lower than the total mass of the initial nuclei, so part of the mass is converted into energy, according to Einstein's equation:

where

E is the energy released in the process

m is the difference in mass between final products and initial nuclei

is the speed of light

Given the huge value of , we see that in the process of nuclear fusion a tremendous amount of energy is released even for very small values of the mass, m.

Nuclear fusion occurs inside the core of the stars and it is the process responsible for the energy produced by the stars. The main process that occurs inside the core of a star is the fusion of two nuclei of hydrogen into a nucleus of helium.