Ensemble properties of nonadiabatic motion of charged particles in inhomogeneous magnetic fields have been studied, to determine qualitatively how the exact motion of the ensemble departs from the adiabatic motion as the adiabaticity parameter is increased. In particular, this investigation is directed towards determining the parameter domain of validity of the existing two models for nonadiabatic behaviour, (i) the Stochastic Diffusion Model (SDM) of Chirikov (1959,78), and (ii) the Quantum-like Model (QLM) of one of the present authors (Varma 1971,5). It has been found from this study that the predictions of the QLM are well corroborated by the numerical experiments for smaller values of the adiabaticity parameter epsilon , while the SDM presumably takes over for values of epsilon greater than a certain critical value.