Understanding Nuclear Fusion as an Energy Source

Steps:

• Recall that nuclear fusion involves light atomic nuclei combining to form a heavier nucleus, releasing energy.
• Compare this to the choices: identify which describes joining of nuclei.
• Eliminate options related to decay, melting, or splitting, as they describe other nuclear processes.
• Confirm the match with the standard definition of fusion.

Why B is correct:

• Nuclear fusion is defined as the process where two light nuclei join to form a heavier nucleus, releasing energy per Einstein's mass-energy equivalence (E=mc²), powering stars like the Sun.

Why the others are wrong:

• A describes radioactive decay, which emits particles and energy from unstable nuclei without joining.
• C refers to a phase change, not a nuclear reaction; nuclei don't "melt."
• D describes nuclear fission, where heavy nuclei split into lighter ones, as in atomic bombs or reactors.

Final answer: B