An amount of charge q is uniformly distributed spreading over the surface of a disk of radius a. (a) Use elementary methods based on the azimuthal symmetry of the charge distribution to find the potential at any point on the axis of symmetry. (b) With the help of part (a) find an expression for the potential at any point r (r > a) as an expansion in angular harmonics. 2) A sphere of dielectric constant "e" is placed in a uniform electric field. EO. Show that the induced surface charge density is 0 (0) E - Eo ε + 2εo -38oEo cose where 0 is measured from the direction of EO. If the sphere rotates at a speed angular w around the direction of EO, will a magnetic field be produced? if not, explain why no magnetic field is produced. yes it produces, draw the magnetic field lines.