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A single mode dye laser is used to selectively excite individual rotational levels in the $NO2 2B2+2A1$ visible transition. Subsequent time resolved fluorescence polarisation measurements in the presence of fixed magnetic field demonstrate quantum beats between Zeeman sublevels of each excited hyperfine component. A single measurement yields the radiative relaxation rate, the alignment relaxation rate, and the Lande g factor for each hyperfine component. These properties are in accord with simple theory. This experiment bears on discrepancies in previous measurements of these quantities by zero field level crossing (Hanle Effect), optical radio frequency double resonance, and pulsed laser induced fluorescence.