what radius?
Now, I really have to take out the big guns:
Any classical view, and therefore a classical radius of an electron, is an indequate description, and therefore moot.
From a phycisist's point an electron is a point-like particle, where the only best approximation to describe it is its probability density, determined by ψ∗ψ ́ = |ψ|^2 (Schrödinger equation).
Since, we know that there is never any chance to clearly say to absolute accuracy where the electron is (see "Heisenberg uncertainty principle"), the electron might be in the MBA or might still be in the in the charger. It is therefore entirely to the electron to decide where it wants to be.
Obviously, the more obedient electrons are highly-priced (ever looked at your energy bill? The more electricity you consume, i.e. electrons that volunteer to work in your appliances, the higher it is.), and Apple can market a 85W "capable" charger, but it would be prohibitively expensive, even for
's price-tags on their chargers, to afford enough willing electrons.
-Drsoong