According to Hubble's law, the recessional velocity of a distant galaxy is proportional to its distance from Earth. If a graph of recessional velocity is plotted on the vertical axis against distance on the horizontal axis, which physical quantity is represented by the gradient of the line?
The age of the Universe
The Hubble constant
The speed of light
The critical density of the Universe
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.