Maximum current and Electric field in wire

[leggomaeggo]

Please someone help me, i posted here before and got no reply :(

How do you find the maximum current and the largest electric field in the wire for the bottom question?

Two 10-cm-diameter metal plates are 1.0 cm apart. They are charged to +/-12.5 nC. They are suddenly connected together by a 0.224-mm-diameter copper wire stretched taut from the center of one plate to the center of the other.

 

[cloakblade5]

B = $$\mu$$_oI$$/$$2$$\pi$$r

B is magnetic field, I is current, r is radius of the magnetic field(i think), and $$\mu$$₀ is equal to 4$$\pi$$ x 10^-7

Those pi's aren't superscripted, it is just being difficult.