A disk with uniform surface charge density σ = −8.60 μC/m2 is oriented as shown in the diagram below. The field at a distance y from the center of a disk (of radius r = 0.420 m ) and along its axis is given by E = σ2 ε0(1−yy2+r2), where ε0 = 8.85×10−12 C2 /(N⋅m2) is the permittivity of free space. What is the electric potential at a location P whose coordinates are (0, 0.115 m) ? Take the electric potential at infinity to be zero. V
![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)
