A student claims that the emf induced in a straight conductor moving through a uniform magnetic field can be interpreted in two alternative but equivalent ways.
(i) Explain, with the help of the Lorentz force acting on free charges, how an electric potential difference is established between the ends of a moving conductor.
(ii) Show that the same magnitude of emf can be obtained by considering the change in magnetic flux through the area swept by the conductor in a small time interval.
(iii) Comment on the physical significance of the negative sign that appears in the flux-change formulation of electromagnetic induction.