Question

what is the difference between resistance and resistivity?

Answer 1

Resistance is ratio of potential difference across a component to the current passing through it. It is measure of components resistance to the flow of electric charge. It is extensive property of a component which depends on the size or shape of the component.
Resistivity is measure of materials ability to oppose the flow of electric charge. It is intensive property of a component which is independent of the shape or size of the component.

Answer 2

Resistance is the term which is the resisting of flowing of charges from a specific substance of any size.

Consider we have a solid substance of copper. It will have a resisting of charges from flowing through the substance.

If we change its length and area provided to drift of charge, its resistance will vary.

But the one thing that will constant for all copper substance of any shape and size is resistivity. The resistance of a substance of copper , iron , germanium will vary if we change the shape and size of that substance, but its resistivity is constant at any shape and size.

Resistivity is different in copper,Iron etc because of their nature,but if we change the shape,only resistance will change.

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Resistivity is like the density of a material that is constant and resistance is like the mass which will depend on the length area or (volume) of substance.