Assume that the researchers place an atom in a state with n = 100, l = 2. What is the magnitude of the orbital angular momentum L̅(vector) associated with this state?

(a) √2 ℏ;

(b) √6 ℏ;

(c) √1200 ℏ;

(d) √110,100 ℏ.

In photosynthesis in plants, light is absorbed in light-harvesting complexes that consist of protein and pigment molecules. The absorbed energy is then transported to a specialized complex called the reaction center. Quantum-mechanical effects may play an important role in this energy transfer. In a recent experiment, researchers cooled rubidium atoms to a very low temperature to study a similar energytransfer process in the lab. Laser light was used to excite an electron in each atom to a state with large n. This highly excited electron behaves much like the single electron in a hydrogen atom, with an effective (screened) atomic number Z_eff = 1. Because n is so large, though, the excited electron is quite far from the atomic nucleus, with an orbital radius of approximately 1 mm, and is weakly bound. Using these so-called Rydberg atoms, the researchers were able to study the way energy is transported from one atom to the next. This process may be a model for understanding energy transport in photosynthesis.