Question

What is a conductor? How is the conductivity relatd to resistance? How does conductivity of a regular conductor (like a copper wire) change with temperature? Why? (Hint: think about how electrons collide with vibrating atoms.) (please write the answer clear and with a good handwriting thanks!)

Answer 1

A conductor(specifically electrical) is an object or material which allows charges to flow through it.

Conductivity is ability of object or material to conduct an electric current (i.e. flow of charge) through it.

we know,

R = ρ (L/A)

where ρ is resistivity. And conductance is reciprocal of resistivity.

therefore,

R = (1/C) (L/A)

=> C = L/(RA)

when length L and area A are constant, Conductance C is inversely proportional to resistance.

That is, C ∝ 1/R

Conductivity for a regular conductor decreases with increase in temperature.

Reason: The kinetic energy of electron increases thus the speed also vibration of positive ions increases about there mean position. This results in more frequent collisions reducing the relaxation time for electron. Less the relaxation time means more the randomness. For a current to flow there need be flow in single direction but due to randomness direction of electrons are in every direction which as result increase resistivity and decrease conductivity.