4*. For a uniform sphere of charge with radius R the electric field is E = where Q is the total charge of the sphere. Using V = integrate along a radial path (dr = dry) to find V(r). Do this first with reference at infinity and then with reference at the center of the sphere. Your answers should just differ by a constant. What is this constant? 5. Using the following expression for electric potential V = ATED find the electric potential a distance z above the center of a disk with radius R and uniform charge density o: 6. Consider a finite line charge with uniform charge density A and length L: L a) Using the following expression for electric potential V = ATEOJ find the electric potential a distance r to the right of the line charge at the point P. b) Show that if c > > [ your answer to part a) looks like the electric potential of a point charge. The following might be helpful: In (1 + 2) = 2 - 23 + 7 23 + ... for -1