We note an area-charge inequality orignially due to Gibbons: if the outermost
horizon S in an asymptotically flat electrovacuum initial data set is
connected then β£qβ£β€r, where q is the total charge and r=A/4Οβ
is the area radius of S. A consequence of this inequality is that for
connected black holes the following lower bound on the area holds: rβ₯mβm2βq2β. In conjunction with the upper bound rβ€m+m2βq2β which is expected to hold always, this implies the natural
generalization of the Riemannian Penrose inequality: mβ₯1/2(r+q2/r).Comment: 4 pages; 1st revision, added a generalization, added a reference; 2nd
revision, minor correction