Learning objectives
Define luminosity as the total power radiated by a star, and use F = L/(4πd²) to relate the radiant flux intensity received at the Earth to luminosity and distance.
Explain what a standard candle is and how the measured flux from a standard candle of known luminosity gives the distance to a galaxy.
Estimate the surface temperature of a star from the wavelength at which its spectrum peaks, using Wien's displacement law λmax ∝ 1/T.
Calculate the radius of a star of known luminosity by combining the Stefan–Boltzmann law L = 4πσr²T⁴ with a surface temperature found from Wien's law.
Continue with a revision plan
These learning objectives are available to everyone. Sign in with an eligible plan to read the full note and worked examples.