An astrophysicist studying a distant active galactic nucleus (AGN) identifies a prominent Hydrogen-beta (HβH\betaHβ) emission line in its spectrum. In the laboratory, this line has a rest wavelength of 486.1 nm486.1\text{ nm}486.1 nm, but in the observed spectrum of the AGN, the line is detected at a wavelength of 512.5 nm512.5\text{ nm}512.5 nm.
What is the recessional speed of this AGN?
1.5×107 m s−11.5 \times 10^7\text{ m s}^{-1}1.5×107 m s−1
1.6×107 m s−11.6 \times 10^7\text{ m s}^{-1}1.6×107 m s−1
1.6×104 m s−11.6 \times 10^4\text{ m s}^{-1}1.6×104 m s−1
3.2×108 m s−13.2 \times 10^8\text{ m s}^{-1}3.2×108 m s−1
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.