Ohm's Law

Ohm's law is one of the most important laws in electronics.  

It is what defines the relationship between voltage, current and resistance.

It is simply stated as follows:

`V=IR`

This is a LAW, meaning that it is established as fact.  A scientific law is a law because we say so.  V will always equal IR.  Even if some day the coulomb is redefined, Ohm's law will remain as stated.  Laws are not mathematic representations based on observations.  Laws are mathematical fact that define the relationship.  

Think of a law as "because we said so."  The sky is blue because someone defined the sky as blue.  The color blue is the name of the color of the sky because we said it was.  No other reason.