  We study physical processes around a rotating black hole in pure Gauss-Bonnet
(GB) gravity. In pure GB gravity, gravitational potential has slower fall off
as compared to the corresponding Einstein potential in the same dimension. It
is therefore expected that the energetics of pure GB black hole would be
weaker, and our analysis bears out that the efficiency of energy extraction by
Penrose process is increased to $25.8\%$ and particle acceleration is increased
to $55.28\%$, and optical shadow of the black hole is decreased. These are the
distinguishing in principle observable features of pure GB black hole.
