Resistance (R) : any conductor that opposes the flow of electric current through it and depends on the shape and size of the materials, temperature, and nature of the materials is called resistance (R).
- R = ρL/A where ρ – resistivity, L – length and A – area of the cross-section.
- The SI unit of resistance (R) = ohm (Ω).
Resistivity (ρ) : The resistance offered by a wire of unit length and unit area of cross-section is called resistivity (ρ) or specific resistance (r).
- The SI unit of resistivity (ρ) = Ohm-meter (Ω-m).