1. The problem statement, all variables and given/known data an electric field is uniform,and in the positive x direction for positive x,and uniform with the same magnitude but in the negative x direction for negative x.it is given that vector E=200 I^ (N/C) for x>0 and vector E= -200 (N/C) for x<0 .A right circular cylinder of length 20 cm and radius 5 cm has it's center at the origin and it's axis along the x-axis so that one face is at x=+10 cm and the other is at x=-10 cm a)what is the flux through the side of the cylinder? b)what is the net outward flux through the cylinder? 2. Relevant equations 3. The attempt at a solution a)in my book it has been given that Vector E is parallel to sides of cylinder so flux through sides =0 My understanding regarding this explanation of Vector E to be parallel to sides of cylinder is to point out that that electric fields do not even pass through sides of cylinder because the angle between vector E and area vector of sides of cylinder is 90 degrees so no flux.Am I correct? b)net outward flux=flux through faces (as flux through sides is zero) =vector E.vector A +vector 'E.vector A =0 But solution of this is given to be =2EA =3.14 Nm^2/C I don't understand why?why magnitude of 'E is taken as 200 N/C but not -200 N/C I thought negative sign is part of magnitude because it does not symbolize/indicate direction as direction is specified by vector i.