Some geometrical aspects of the Kerr-Newman black hole and its special cases have been studied. It is seen that the Gaussian curvature of the two or three dimensional induced metrics on some hypersurfaces outside of these black holes can be expressed in terms of the eigen values of the characteristic equation and depend upon the physical parameters which describe these black holes.
The authors are grateful to Dr. A. H. Hasmani, Sardar Patel university, Vallah Vidyanagar (Gujrat) for verifying equations (B1 − B12) through MATHEMATICA.
"Geometry of charged rotating black hole." SUT J. Math. 49 (2) 129 - 143, June 2013. https://doi.org/10.55937/sut/1393504860