Chapter 23, Problem 31P

ILW Two long, charged, thin-walled, concentric cylindrical shells have radii of 3.0 and 6.0 cm. The charge per unit length is 5.0 × 10⁻⁶ C/m on the inner shell and −7.0 × 10⁻⁶ C/m on the outer shell. What are the (a) magnitude E and (b) direction (radially inward or outward) of the electric field at radial distance r = 4.0 cm? What are (c) E and (d) the direction at r − 8.0 cm?