The degree of Zeeman splitting of ground-state sublevels in the presence of a magnetic field can be measured using atomic sensors. The coherence of the spins in the ensemble affects the efficiency of an atomic magnetometer. The sensitivity of these sensors depends on the line width of the magnetic resonance curve, which is related to the coherence lifetime of the atomic spins. Atomic polarization influences the optical properties of the medium, making it anisotropic. The relatively long lifetime of ground-state polarization is a useful tool for measuring the energy-level splitting. The modification associated with the atomic coherence in the presence of an external magnetic field leads to interesting absorption effects in the atomic environment. The splitting of magnetic sublevels and the transition between them under the application of a magnetic field are quantum mechanical images of the interaction between a field and an atomic spin that must be analyzed using a density matrix. In the present work, magneto-optical effects with circularly polarized light such as the dynamic properties and evolution of sublevels of the rubidium-87 D1 line and the absorption properties of the atomic polarized environment are studied theoretically using the reduced density matrix approach.