From the angle of uncertainty relation,the difficulties in quantization of angular variation in quantum mechanics are analyzed.Hence,the contradiction between quantization of angular momentum and current theory of uncertainty relation is found.
An elementary approach to the quantum theory of angular momentum is sketched. The quantization of angular momentum components, Heisenberg-type inequalities for their spectral dispersions, and the quantization of the angular momentum modulus are introduced without using operators or commutation relations. The purpose is to focus the attention on angular momemtum as a very important practical concept of quantum physics, as well as on its specifically quantum-theoretical aspects, right from the beginning of an introductory course. Since the heuristic arguments employed here closely parallel the rigorous derivations of a formal approach, the intuitive presentation does not contradict, but rather supports, the theoretical concepts to be introduced at a later stage.