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.
25 exam-style questions on CIE IGCSE Physics 6.2.2a Galaxies and astronomical distances. Each one has a worked solution and a mark scheme showing where the marks go.