Resistivity

Definition

Resistivity is a measure of how strongly a material opposes the flow of electric current. It is denoted by the Greek letter $\rho$ (rho) and has units of ohm-meters ($\Omega \cdot m$).

5 Must Know Facts For Your Next Test

1. Resistivity is intrinsic to the material and does not depend on its shape or size.
2. The resistivity of a material increases with temperature for conductors, but decreases with temperature for semiconductors.
3. Resistivity can be calculated using the formula $\rho = R \frac{A}{L}$, where $R$ is resistance, $A$ is cross-sectional area, and $L$ is length.
4. Materials with low resistivity are good conductors of electricity, while materials with high resistivity are good insulators.
5. Copper and aluminum have low resistivities and are commonly used in electrical wiring.

Review Questions

• What is the definition of resistivity?
• How does temperature affect the resistivity of conductors and semiconductors?
• Provide the formula to calculate resistivity and explain each term in it.

Related terms

Resistance:

Resistance is a measure of how much a material opposes the flow of electric current through it. It depends on both the material's properties and its shape.

$Ohm's \ Law$: $Ohm's \ Law$ states that the current through a conductor between two points is directly proportional to the voltage across the two points, expressed as $V = IR$, where $V$ is voltage, $I$ is current, and $R$ is resistance.

Conductivity:

Conductivity is a measure of a material's ability to conduct electric current. It is the reciprocal of resistivity.