Someric cross-section ratios of evaporation residues formed in¹²C+⁹³Nb and ¹⁶O+⁸⁹Y reactions were measure by recoil catcher technique followed by oÆ-line∞-ray spectrometry in the beam energy range of 55.7-77.5 MeV for ¹²C and 68-81 MeV for ¹⁶O. The isomeric cross-section ratios were resolved into that for complete and incomplete fusion reactions. The angular momentum of the intermediate nucleus formed in incomplete fusion was deduced from the isomeric cross-section ratio by considering the statisticalde-excitation of the incompletely fused composite nucleus. The data show that incomplete fusion is associated with angular momenta slightly smaller than critical angular momentum for complete fusion, indicating the deeper interpenetration of projectile and target nuclei than that in peripheral collisions