A thick cylindrical shell of inner radius a= 5 cm and outer radius b= 10 cm and has a net charge ZERO. A thin line with a linear charge density + 4.5*10^-3 C/m is stretched along the axis of the shell.
A) Find the electric field at the radial distance r=3cm, r=7cm, r=13cm?
B) Consider 1m length of the cylinder and find the inner and the outer surface charge densities?