Consider a two level atom interacting with the interaction Hamiltonian of the form hatH = hatV_0 cos( omega t). The probability of the state to be in the excited state is given by P_e = frac nu² Omega_R² hbar² sin² bigg( frac Omega_Rt2 bigg) with Omega_R = [ Delta² + nu² / hbar² ]¹/2 and nu = with Delta = omega - omega_0. The plot of Probability vs time for various values of Delta is given. When the detuning factor Delta is non-zero, i.e., Delta increases, the amplitude of the probability decreases and the time taken for revival and collapse decreases. Physically, Why does the probability decrease and the frequency of collapse/revival increase because of increasing Delta?