Which process is responsible for production of energy in stars?

Analysis

The question asks for the specific physical process that powers stars, including our Sun. We need to distinguish between different types of nuclear processes to identify which one occurs under the extreme conditions found in stellar cores.

Concept Explanation

To understand how stars produce energy, we look at Nuclear Physics:

1. Nuclear Fission: This is the process where a heavy, unstable nucleus (like Uranium-235) splits into smaller, lighter nuclei, releasing energy. This is the principle used in nuclear power plants and atomic bombs.
2. Nuclear Fusion: This is the process where two light atomic nuclei (typically hydrogen isotopes like deuterium and tritium) combine or "fuse" together under immense heat and pressure to form a heavier nucleus (like helium). This process releases a massive amount of energy according to Einstein’s mass-energy equivalence principle ($E = mc^2$).
3. Radioactive Decay: This is the spontaneous breakdown of an atomic nucleus resulting in the release of energy and matter from the nucleus. While it occurs in stars, it is not the primary source of their massive energy output.

Step-by-Step Solution

• Step 1: Identify the conditions in a star. Stars have extremely high temperatures and pressures at their cores.
• Step 2: Evaluate the processes. The high temperature and pressure are sufficient to overcome the electrostatic repulsion between positively charged protons, allowing them to collide and fuse.
• Step 3: Compare the processes. While "Nuclear reaction" (Option A) is a broad term that includes fusion, "Nuclear fusion" (Option C) is the specific, scientifically accurate process responsible for stellar energy production.
• Step 4: Conclusion. Because stars fuse hydrogen atoms into helium, the correct process is nuclear fusion.

Identification of the Answer

The correct option is C.

Exam Tip

When you see questions about energy in stars, always look for the word "Fusion". A simple way to remember it is: Fusion = Fuse together (making something bigger), while Fission = Fissure/Split (making something smaller).