An insulating solid sphere of radius a has a uniform volume charge density and carries a total positive charge q. a spherical gaussian surface of radius r, which shares a common center with the insulating sphere, is inflated starting from r # 0. (a) find an expression for the electric flux passing through the surface of the gaussian sphere as a function of r for r , a. (b) find an expression for the electric flux for r - a. (c) plot the flux versus r.