Past exam of the short options paper shared by Prelims and Parts A and B of the physics course of the University of Oxford / 2016 / S26 / 3 / 4 / Solution

Use an explicit Tully-Fisher-type scaling $L\propto v_{\max }^4$ for comparable spiral populations and photometric band. Relative to the preceding galaxy,The exponent and normalization are empirical and have scatter; one galaxy alone does not establish the relation. Different stellar populations, inclination errors and extinction change the photometric inference.