Nuclear Fusion Powers the Sun

Steps:

• Identify the process: Fusion of hydrogen nuclei into helium releases energy via E=mc², converting mass to energy.
• Recall stellar energy source: This reaction occurs in stars where high pressure and temperature enable fusion.
• Evaluate locations: Nuclear power stations use fission, not fusion; Earth's core involves radioactive decay; alpha emission is decay, not fusion.
• Select match: Only the Sun's core provides conditions for sustained hydrogen-helium fusion.

Why D is correct:

• The Sun's core has extreme heat (15 million°C) and pressure, per the proton-proton chain reaction, fusing hydrogen into helium and releasing energy as light/heat.

Why the others are wrong:

• A: Nuclear power stations rely on uranium fission, not hydrogen fusion.
• B: Alpha particle emission is radioactive decay in isotopes like uranium, not fusion.
• C: Earth's core heat comes from radioactive decay and residual formation energy, not fusion.

Final answer: D