Which of the following describes the nuclear reaction that supplies the primary source of energy in a main-sequence star?
The nuclear fission of helium nuclei into hydrogen nuclei.
The nuclear fission of heavy radioactive isotopes like uranium.
The nuclear fusion of hydrogen nuclei into helium nuclei.
The nuclear fusion of helium nuclei into hydrogen nuclei.
104 exam-style questions on CIE IGCSE Physics 6.2 Stars and the Universe, covering 6.2.1 The Sun as a star, 6.2.2a Galaxies and astronomical distances, 6.2.2b The life cycle of a star, 6.2.3a Galaxies and the scale of the Universe, 6.2.3b Redshift, 6.2.3c The Big Bang Theory and cosmic microwave background radiation, and 6.2.3d The Hubble constant and the age of the Universe. Each one has a worked solution and a mark scheme showing where the marks go.