Observed rotation (symbol: α) of a sample of a compound is the angle by which it rotates the plane of polarized light, measured using the polarimeter. Observed rotation of a sample of a compound depends on the
- concentration, if a solution is used for the for the experiment, or density if the sample is neat
- solvent, if a solution is used for the experiment
- length of the sample tube
- wave length of the light.
see also specific rotation