Multiple choice

The main source of energy of the sun is

  1. fusion of heavy nuclei

  2. fusion of light nuclei

  3. fission of light nuclei

  4. both fusion and fission
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Sun's energy is produced by nuclear fusion of light nuclei - specifically, hydrogen nuclei (protons) fusing to form helium in the core. This process releases enormous energy because the mass of helium produced is slightly less than the mass of four hydrogen nuclei, with the difference converted to energy (E=mc²).

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