- (a) A conducting rod of length L is moved with speed v at right angles to a uniform magnetic field of flux density B. The field is directed into the plane of the page.
conducting rod moving perpendicular to magnetic field
(i) Show, using Faraday’s law or otherwise, that the potential difference, V, established between the ends of the rod is V = vBL. [1]
(ii) Identify the end of the rod that becomes negatively charged. [1]
(b) A coil is rotating in a region of magnetic field with angular speed 12.56 rad s⁻¹. At t = 0, the field is parallel to the surface of the coil.
(i) State the magnetic flux linkage through the coil at t = 0. [1]
(ii) Draw, on the axes, a graph to show the variation with time of the induced emf in the loop. (No numbers are required on the vertical axis.)
(c) A capacitor is connected to a cell. The switch S is closed and the capacitor becomes fully charged.
capacitor connected to cell with switch
A dielectric is then inserted in between the plates of the capacitor. Suggest what, if anything, will happen to the charge on one plate of the capacitor. [1]