Light absorption in molecules is based on interaction between the electrical oscillation of the light and the electrical dipole oscillation of the molecule. In liquids and solids, molecules are free to move or rotate as they please and the dipole vectors reorient as they do so.

Suppose a vector begins with orientation 1 √
3 (1, 1, 1), but ends with orientation (1, 0, 0). Calculate how much the vector has been rotated by (i.e., calculate the angle between the initial and final vectors).