Question: a parallelplate capacitor made of two disc shaped plates of...
A parallel-plate capacitor made of two disc shaped plates of diameter R has a small spacing d between the plates
where R >> d. It is charged by a current I. Derive an expression for the magnetic field as a function of r the radial
distance from the axis of the capacitor. Recall that the electric field inside a parallel plate capacitor is E = σ/(ε0) where σ is the surface charge Q/A (Q is the total charge in the capacitor and A is the area).