Bekenstein-Hawking entropy by energy quantization from Reissner-Nordstrom black hole

We consider the motion of a test particle orbiting around Reissner-Nordstrom (RN) black hole spacetime. The complete set of equations for radial motion and effective potential is derived. We also derive the radius of the different stable circular orbits of this particle corresponding to different label indexes like the Bohr atomic model. We also quantized the energy of this particle from the quantization of angular momentum and calculated the Bekenstein-Hawking entropy of RN black hole. We also investigate the change of entropy between two nearby states approaches to zero for large quantum numbers.