1)
if they obey , then why is the drop across a ideal diode constant even when the current in it changes?
The R changes. You need to look at the V-I curve.
2) I heard someone say in another thread "semiconductors obey ohms law , but semiconductor junctions dont". why is it so?
I think they both do.
3) A thread in another forum said that liquids dont obey ohms law as ions are the current carriers...
true or false?
Solids and liquids have a bulk resistivity, so they obey Ohm's law.
4) Is ohm's law a special case of V=IR or is V=IR a special case of ohms law?
??
5) Is Ohms law a law at all?
Well, it's falsifiable
Falsifiability - Wikipedia, the free encyclopedia
6) Is there any theory in physics which explains why ohms law works the way it does?