The electric field along the axis of a ring-shaped charge of total charge q distributed uniformly is given by E = qz 4πε0(z2 + R2)3/2, where R is the radius of the ring and z is the distance from the center of the ring. The electric field at the center of the ring is zero and at great distances from the ring approaches zero. At a certain distance along the z-axis the electric field strength is maximum. What is the electric field strength at this point?
![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)
