1. The problem statement, all variables and given/known data An infinitely long cylindrical shell of radius 6.0 cm carries a uniform surface charge density sigma = 12 nC/m^2. The electric field at r = 5.9 cm is approximately a.0.81 kN/C b.zero. c.1.3 kN/C. d.12 kN/C. e.0.56 kN/C. 2. Relevant equations See below. 3. The attempt at a solution Will the correct choice be b. 0? I am assuming that this is a conducting cylindrical shell. When r < R, E will be 0. 1. The problem statement, all variables and given/known data An infinitely long cylinder of radius 4.0 cm carries a uniform volume charge density rho = 200 nC/m^3. What is the electric field at r = 8.0 cm? a.0.23 kN/C b.0.11 kN/C c.57 kN/C d.0.44 kN/C e.zero 2. Relevant equations electric flux = Integral [E*dA] = Q_enclosed/epsilon_0 3. The attempt at a solution I sloshed through this one because I mixed up the radii (r and R) at first. Did I eventually get the correct answer? Q_enclosed = rho*2*pi*R^2*l flux = E*2*pi*r*l E*2*pi*r*l = (rho*2*pi*R^2*l)/(epsilon_0) E = (rho*R^2)/(r*epsilon_0) = (200*10^-9 c/m^3)(0.04 m)^2/[0.08 m*8.85*10^-12] = 452 N/C?? Thanks.