  We construct a gedanken experiment in which an extremal Kerr black hole
interacts with a test electromagnetic field. Using Teukolsky's solutions for
electromagnetic perturbations in Kerr spacetime, and the conservation laws
imposed by the energy momentum tensor of the electromagnetic field and the
Killing vectors of the spacetime, we prove that this interaction cannot convert
the black hole into a naked singularity, thus cosmic censorship conjecture is
not violated in this case.
