24 Figure 23-40 shows a section of a long thin-walled metal tube of radius R = 3.00 cm; with a charge per unit length of λ = 2.00 x 10^-8 C/m. What is the magnitude E of the electric field at radial distance (a) r = R/2.00 and (b) r = 2.00R? (c) Graph E versus r for the range r = 0 to 2.00R.