Resistance: Resistance is the measure of how much an object or material impedes the flow of electric current. It depends on both resistivity and the physical dimensions (length and cross-sectional area) of the object.
Conductivity: Conductivity is the opposite of resistivity. It measures how easily a material allows electric current to pass through it. Materials with high conductivity have low resistivity.
Ohm's Law: Ohm's Law states that there is a linear relationship between voltage, current, and resistance in an electrical circuit. It can be expressed as V = IR, where V is voltage, I is current, and R is resistance.