A capacitor has circular plates of radius \(r = 12\,cm\) that are now a distance \(d = 0.2\,cm\) apart.
If this particular capacitor is hooked up to a \(12\,V\) battery, what is the value of the Electric Field between the two plates in \(N/C\)?
C=ε₀A/d
C=q/U=>
q=CU = ε₀AU/d
E=σ/2ε₀ =q/A•2ε₀=
= ε₀AU/d•A•2ε₀=U/d
The same result may be obtained from
E=-gradΔU =>
E=ΔU/Δx =U/d