Solar energy is due to _______ reactions?

(A) Nuclear fusion

(B) Nuclear fission

(C) Combination of nuclear fusion and fission

(D) Chemical

Composition of the Sun

• Like other stars, the Sun is a massive ball of gas.
• By number of atoms, it contains about 91% hydrogen and 8.9% helium.
• By mass, it is approximately 70.6% hydrogen and 27.4% helium.

Fission vs. Fusion

• Fission: The splitting of a heavy, unstable nucleus into two lighter nuclei, releasing energy.
• Fusion: The combining of two light nuclei into a heavier nucleus, releasing enormous amounts of energy.
• Both are nuclear reactions that generate energy, but the processes and conditions differ.

Nuclear Fusion in the Sun

• In the core of the Sun, extreme temperature and pressure allow hydrogen nuclei (protons) to collide and fuse into helium nuclei.
• This fusion reaction releases tremendous energy in the form of light and heat, which powers the Sun and provides energy to Earth.
• Fission, though also an energy-releasing process, is not the primary energy source in the Sun because conditions favor fusion instead.

Correct Answer: Option A