  We study scalar and electromagnetic perturbations of a family of nonsingular
nonrotating black hole spacetimes that are solutions in a large class of
conformally invariant theories of gravity. The effective potential for scalar
perturbations depends on the exact form of the scaling factor. Electromagnetic
perturbations do not feel the scaling factor, and the corresponding quasinormal
mode spectrum is the same as in the Schwarzschild metric. We find that these
black hole metrics are stable under scalar and electromagnetic perturbations.
Assuming that the quasinormal mode spectrum for scalar perturbations is not too
different from that for gravitational perturbations, we can expect that the
calculation of the quasinormal mode spectrum and the observation with
gravitational wave detectors of quasinormal modes from astrophysical black
holes can constrain the scaling factor and test these solutions.
