An absorption line in the spectrum of light from a distant galaxy is observed at a wavelength of 525 nm525\text{ nm}525 nm. In a laboratory on Earth, the same absorption line is measured at a rest wavelength of 500 nm500\text{ nm}500 nm.
Which of the following correctly identifies the cosmological redshift z z\,z of this galaxy and the physical system whose expansion is supported by this observation?
Redshift z=0.048z = 0.048z=0.048; expansion of the Solar System
Redshift z=0.050z = 0.050z=0.050; expansion of the Universe
Redshift z=0.048z = 0.048z=0.048; expansion of the Universe
Redshift z=0.050z = 0.050z=0.050; expansion of the Solar System
Practise Edexcel GCSE Physics The Big Bang, red-shift and the expanding Universe with exam-style questions for Foundation and Higher tier. 80 questions, matched to the Edexcel GCSE Physics (1PH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.