An astrophysicist studying a distant active galactic nucleus (AGN) observes a hydrogen spectral line, which has a laboratory rest wavelength of 500.0 nm500.0\text{ nm}500.0 nm, shifted to an observed wavelength of 485.0 nm485.0\text{ nm}485.0 nm in the AGN's spectrum.
Which row correctly identifies the speed, vvv, of the AGN relative to Earth and its direction of motion?
(Take the speed of light in a vacuum, ccc, to be 3.00 × 108 m s-1)
Speed: 9.0×106 m s−19.0 \times 10^6\text{ m s}^{-1}9.0×106 m s−1 | Direction of motion: moving away from Earth
Speed: 9.0×106 m s−19.0 \times 10^6\text{ m s}^{-1}9.0×106 m s−1 | Direction of motion: moving towards Earth
Speed: 9.3×106 m s−19.3 \times 10^6\text{ m s}^{-1}9.3×106 m s−1 | Direction of motion: moving away from Earth
Speed: 9.3×106 m s−19.3 \times 10^6\text{ m s}^{-1}9.3×106 m s−1 | Direction of motion: moving towards Earth
27 exam-style questions on OCR GCSE Physics Beyond Earth. Each one has a worked solution and a mark scheme showing where the marks go.