5. The current density in a particle beam with circular cross section of radius a points along the beam axis with a magnitude that decreases lincarly with Jo at the center r = 0 to half that value at the edge r = a. (a) Find a lincar function J (r) that describes the particle beam. (b) Find an expression for the total currcnt in the beam.

5. The current density in a particle beam with circular cross section of radius a points along the beam axis with a magnitude that decreases lincarly with Jo at the center r = 0 to half that value at the edge r = a. (a) Find a lincar function J (r) that describes the particle beam. (b) Find an expression for the total currcnt in the beam.