The electric field in a region around the origin is given by E→ = C(xi^ + yj^), where C is a constant. The equipotential surfaces are: concentric cylinders with axes along the z axis concentric cylinders with axes along the x axis concentric spheres centered at the origin planes parallel to the xy plane planes parallel to the yz plane
![A total charge Q is uniformly distributed, with surface charge density σ, over a very thin disk of radius R. The electric field at a distance d along the disk axis is given by E→ = σ2ϵ0[1−dd2+R2]n^ where n^ is a normal unit vector perpendicular to the disk. What is the best approximation for the electric field magnitude E at large distances from the disk? a) σ2ϵ0 b) QRϵ0 d2 c) σR4ϵ0 d d) σϵ0(R2 d)2 e) none of the above](https://www.doubtrix.com/uploads/editor/0675279737hrIrQWHgba.png)