Ohm's Law deals with the relationship between voltage and current in an ideal conductor. This relationship states that:
The potential difference (voltage) across an ideal conductor is proportional to the current through it.
The constant of proportionality is called the "resistance", R.
Ohm's Law is given by:
V = I R
Coulomb's law predicts that the force exerted by one point charge on another is proportional to the product of the two charges.By changing one charge while keeping other things constant and seeing if the force is proportional to it.
Try this ohms law calculator app through which you can easily came to know about the calculations of voltage,current and resistance.