What causes Nichrome to have more resistance than Copper?

Question

Suppose,we have two wires of equal length and the same cross sectional,one made up of nichrome and the other made up of copper metal. Then, nichrome wire will have more resistance than the copper wire.

So,what is inside the nichrome wire that causes them to have more resistance than copper even if the wires are of same length and same cross sectional area?

I think the nichrome wire has less free electrons in their atoms.So,the number of collisions increase and it's resistance increase.PLease correct me if i am wrong.

Kindly tell me what is the difference between copper and nichrome which makes nichrome to have more resistance than copper even if the wires are of same length and same cross sectional area?

Answer 1

First copper is an element and nichrome is an alloy primarily of nickel,chromium and iron. So that's the first clue noting that the three elements that make up this alloy have a smaller conductivity than copper.

But there's more to the reason for higher resistance. The manner in which the three elements make up the nichrome alloy results in grain boundaries, dislocations and voids that interrupt the crystal lattice of the alloy which for pure copper is much more uniform. These differences of the crystal lattices either allow smooth flow of electrons as in copper or scattering as in nichrome. Scattering is the dominant effect that leads to the higher resistance, combined with the basic differences in constituent conductivities.