Difference between Resistance and resistivity

In summary, resistivity is a specific property of a material, defined as the ratio of electric field to current density. Resistance, on the other hand, is a measure of the resistivity over a unit length and area. While resistance is dependent on the dimensions of a material, resistivity is a constant property that can be used to calculate resistance.
  • #1
SpartanG345
70
1
What is the difference between these 2 quantities?

from my textbook defines resistivity as a specific property of a material
and is = E/J

where the resistance is the resistivity over a unit length and area. So I suppose the resistance is a measures of resistivity over a volume

Resistance = pL/A

thats what i think but i am not sure if i am right

PS i am sorry if this is a noob question, but my answer differed by one provided on yahoo answers, but then again yahoo answers is only yahoo answers( i got worried)
 
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  • #2
SpartanG345 said:
Resistance = pL/A
This is what you need. Resistance of a piece of material is proportional to its length and inversely proportional to its area. The proportionality constant p is called the resistivity, which is a property of the kind of material.

Read this: http://hyperphysics.phy-astr.gsu.edu/HBASE/electric/resis.html#c2"
 
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  • #3
Resistance is a property of a device and resistivity is a property of a material. For a mechanical analogue you might think of the difference in strength between a piece of aluminum foil and an aluminum baseball bat. They are both made out of aluminum, so they both have the same Young's modulus, but they are shaped differently so they have different stiffness.
 
  • #4
SpartanG345 said:
What is the difference between these 2 quantities?

from my textbook defines resistivity as a specific property of a material
and is = E/J

where the resistance is the resistivity over a unit length and area. So I suppose the resistance is a measures of resistivity over a volume

Resistance = pL/A

thats what i think but i am not sure if i am right

PS i am sorry if this is a noob question, but my answer differed by one provided on yahoo answers, but then again yahoo answers is only yahoo answers( i got worried)

Suppose you set me this question:What is the resistance of aluminium?I would answer that It's a silly question because it depends on the cross sectional area and the length of the aluminium.If you now asked me what is the resistivity of aluminium I would refer to a data book and come back with an answer.Knowing the resistivity and the dimensions of the aluminium it is easy to work out the resistance.Resistivity,therefore, is a much more useful concept because it is a property of the material and independant of its dimensions.
 

1. What is the difference between resistance and resistivity?

Resistance is the measure of the degree to which a material opposes the flow of electric current. It is dependent on the physical characteristics and dimensions of the material. Resistivity, on the other hand, is an intrinsic property of the material and is a measure of how well a material resists the flow of electric current.

2. How are resistance and resistivity related?

Resistance and resistivity are related through Ohm's Law, which states that the resistance of a material is equal to its resistivity multiplied by its cross-sectional area and divided by its length. In other words, resistance is directly proportional to resistivity and inversely proportional to the material's cross-sectional area and length.

3. What are the units of resistance and resistivity?

The SI unit of resistance is the ohm (Ω), while the unit of resistivity is ohm-meter (Ωm). However, other units such as kilohm (kΩ) and microhm (μΩ) are also commonly used for resistance, and ohm-centimeter (Ωcm) is used for resistivity.

4. How does temperature affect resistance and resistivity?

For most materials, as temperature increases, resistance also increases. This is due to the increase in collisions between the electrons and the atoms of the material. However, for some materials, such as semiconductors, resistance decreases with increasing temperature. Resistivity, on the other hand, usually increases with increasing temperature for most materials.

5. What are some practical applications of resistance and resistivity?

Resistance and resistivity are important concepts in the fields of electrical and electronic engineering. They are used in designing and analyzing circuits, determining the conductivity of materials, and calculating voltage drops in electrical systems. They are also used in the production of resistors, wires, and other electronic components.

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