The electric field of the charged wall board we use in lab has a magnitude of about 2.8×105 n c . the electrophorus is a conducting slab placed in this field. imagine the electrophorus held slighly above the wall board. (a)compute the surface charge density on the bottom surface of the electrophorus. (b)compute the surface charge density on the top surface of the electrophorus. (c)grounding the electrophorus removes the surface charge density on the top surface. if the electrophorus is round, it has a radius of about 12cm for our average pie pan. how much total charge does a charged electrophorus carry?