Detailed Instructions: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: The spherical harmonics have eigenvalue h-bar2 l (l + 1) under this operator's square. The commutator for operators representing two components of this quantity is plus or minus i h-bar times the operator for its third component. Slater determinants are used to force fermion wavefunctions to be asymmetric as required by one type of this quantity. Hyperfine structure results from one interaction involving this quantity, as does Russell-Saunders coupling and the splitting of signals in NMR. Expanding this quantity in the uncoupled basis requires Clebsch-Gordon coefficients. For 10 points, name this quantity equal to the product of inertial moment and angular velocity.
A:
Science