Light from a laboratory source is incident normally at a diffraction grating. The first-order maximum of a spectral line of wavelength 450 nm450\text{ nm}450 nm is observed at an angle of 24.0∘ 24.0^\circ\,24.0∘ to the normal.
Light from a distant receding galaxy is observed using the same diffraction grating under normal incidence. The recessional velocity of this galaxy is 0.15c0.15c0.15c, where c c\,c is the speed of light in a vacuum.
What is the observed angle of the first-order maximum of this spectral line in the light from the receding galaxy?
27.9∘27.9^\circ27.9∘
27.6∘27.6^\circ27.6∘
24.0∘24.0^\circ24.0∘
20.2∘20.2^\circ20.2∘
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.