During the evolution of the universe, different forms of matter and structure formed at distinct epochs.
Which of the following forms of matter existed 10,000 years10{,}000\text{ years}10,000 years after the Big Bang?
Carbon and iron nuclei
Neutral hydrogen atoms
Free quarks
Helium-4 nuclei
66 exam-style questions on OCR A A Level Physics Astrophysics and cosmology, covering Stars, Electromagnetic radiation from stars, and Cosmology. Each one has a worked solution and a mark scheme showing where the marks go.