Name: Temperature Dependence of Resistivity
Uploaded: 2019-07-19
Duration: 3 min 27 s
Description: It seems intuitive to think that the resistance of a given material changes at different temperatures, but in which direction does this change occur? We find...

Question

Distinguish between resistance and resistivity.

Accepted Answer

Resistance is defined as the property of the conductor which opposes the flow of electric current. It is also defined as the ratio of the voltage applied to the electric current flowing through it. It is defined by Ohm's law as

$R = \frac{V}{I}$ where $V$ = potential across the conductor and $I$ = current in the conductor due to the applied potential.

Its unit is $ohm$

The resistance of a conductor depends on its dimensions, and the nature of the material as well as on the temperature of the conductor. For a conductor, the resistance is directly proportional to the length of the conductor and inversely proportional to the area of cross-section. Its unit is ohm.

Resistivity is defined as the resistance offered by the material per unit length for unit cross-section. Resistivity increases linearly with temperature. It is an intrinsic property of a material and is independent of the dimensions of the conductor. Mathematically it is expressed as

$ρ = R \frac{A}{l}$ Where $A$ = area of cross-section and $l$ = length of the conductor.

Its unit is $ohm - meter$

Distinguish between resistance and resistivity.

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