  We compare the behavior of a charged particle in a gravitational field and
empty space. We resolve the apparent conflict between the Lorentz-Dirac
equation and Larmor's formula of radiation by noting that the former describes
an electron that is itself accelerated by an electromagnetic field. If instead,
a hypothetical particle is considered that is accelerated by a
non-electromagnetic force, Larmor's formula is found to be consistent with the
accelerating particle's equation of motion. We consider the consequences
concerning the equivalence principle and find that it is indeed violated if one
demands that the same electromagnetic field be present in both the
gravitational and accelerating cases; however, if one allows for the external
electromagnetic fields to be different, the validity of the equivalence
principle is restored. In either case, the basic idea behind the equivalence
principle, which leads to a geometrized theory of gravity, remains unaffected.
