The electric field in a certain region of space is given by the vector field E(r ) = E(x, y, z) = (x ? z)xˆ + (z ? y) yˆ V/m Find any two points P( x1 , y 1, z 1) and Q( x2 , y2 , z2 ) such that the electric field at P is perpendicular to the electric field at Q. Evaluate the electric field at each of these two points.