A physics student studies the light spectra of distant galaxies and observes cosmological redshift. Which of the following statements about cosmological redshift is correct?
It is the decrease in the observed frequency of light from galaxies moving towards us, supporting a contracting Universe.
It is the increase in the observed wavelength of light from distant galaxies, providing evidence that the Universe is expanding.
It is the decrease in the observed wavelength of light from receding galaxies, supporting the Steady State Theory.
It indicates that light is shifted towards the blue end of the spectrum as the space between galaxies decreases.
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.