  The mass spectra and decay properties of heavy quarkonia are computed in
nonrelativistic quark-antiquark Cornell potential model. We have employed the
numerical solution of Schr\"odinger equation to obtain their mass spectra using
only four parameters namely quark mass ($m_c$, $m_b$) and confinement strength
($A_{c\bar c}$, $A_{b\bar b}$). The spin hyperfine, spin-orbit and tensor
components of the one gluon exchange interaction are computed perturbatively to
determine the mass spectra of excited $S$, $P$, $D$ and $F$ states. Digamma,
digluon and dilepton decays of these mesons are computed using the model
parameters and numerical wave functions. The predicted spectroscopy and decay
properties for quarkonia are found to be consistent with available experimental
observations and results from other theoretical models. We also compute mass
spectra and life time of the $B_c$ meson without additional parameters. The
computed electromagnetic transition widths of heavy quarkonia and $B_c$ mesons
are in tune with available experimental data and other theoretical approaches.
