State the condition required for a main sequence star to remain stable and constant in size.
Define the Hubble constant.
State the equation that relates the Hubble constant, H0H_0H0, to an estimate of the age of the Universe, TTT.
Calculate an estimate for the age of the Universe in seconds, using a Hubble constant value of 2.3×10−18 s−12.3 \times 10^{-18} \text{ s}^{-1}2.3×10−18 s−1.
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.