Exercise 2 - 5 points A thick spherical shell of inner radius R and outer radius 2R contains electric charge with non-uniform volume density Pv(r) = Pv.0 3(R/r)?|for RET $ 2R with pvo being a constant of physical dimension C/me. The shell is centred at the origin and is located in free space. a) Determine the expression of the electric field strength E(r) at arbitrary locations at distances r E [0, co) from the sphere's centre. (4 points) Hint: Pay attention to the symmetry of the configuration this may allow an alternative to direct integration. b) Show that the determined expression satisfies the continuity of E(7) at spherical surfaces that are concentric with the charged sphere, and of radii r = R and r = 2R. (1 point)