Nuclear Fusion Powers Stars

Steps:

• Nuclear fusion releases energy when light atomic nuclei combine under extreme conditions.
• The process fuses four hydrogen nuclei into one helium nucleus, with a mass defect converting to energy via E=mc².
• This requires high temperatures and pressures found only in stellar cores.
• Evaluate options to identify where hydrogen-helium fusion occurs.

Why D is correct:

• In the Sun's core, the proton-proton chain fuses hydrogen into helium, releasing energy that powers the star, as described by stellar nucleosynthesis.

Why the others are wrong:

• A: Carbon-14 dating involves beta decay of radioactive carbon, not fusion.
• B: Alpha particle emission is radioactive decay from heavy nuclei, releasing energy via fission-like processes, not hydrogen fusion.
• C: Earth's core heat comes from radioactive decay and primordial heat, without conditions for hydrogen fusion.

Final answer: D