almost
You're on the right track, but Ohm's Law says nothing about watts.
Ohm's Law states the relationship between Resistance, Current, and Voltage.
Current=Voltage/Resistance.
Watts=Current*Voltage.
While being derived from Ohm's Law, Ohm's Law states nothing about watts.
And the Big Kicker.......OHM'S LAW ONLY APPLIES FOR DC VOLTAGE!!!!!! Ohm's Law goes out the window with AC electricity.
You have frequency, wavelenth, impedance, inductive reactance,etc. All of those things come into play when you are messing with AC voltage. It's not as simple as DC current.Way more variables that change when current goes down or up.
While I agree your color will not change from dimming the ballast, I'm quite sure It's due to the gas the bulb burns rather than the ballast.