Distinguish, differentiate, compare and explain what is the difference between resistance and resistivity in physics. Comparison and Differences.
Difference Between Resistance and Resistivity
1. The property of the conductor due to which it opposes a flow of current through it is called resistance. The resistivity of a conductor is the resistance of a conductor of unit length and unit area of cross section.
2. The SI unit of electrical resistance is Ohm. The SI unit of resistivity is Ohm-metre.
3. The resistance of a conductor depends on its length and area of cross section. The resistivity of a conductor does not depend on its length and area of cross section.
Resistance of the Material
The flow of charge through any material encounters an opposing force similar in many respects to mechanical friction. This opposition, due to the collisions between electrons and between electrons and other atoms in the material, which converts electrical energy into another form of energy such as heat, is called the resistance of the material. The unit of measurement of resistance is the ohm, for which the symbol is Ω, the capital Greek letter omega.
The resistance of any material with a uniform cross-sectional area is determined by the following four factors:
- Cross-sectional area
The resistance of a piece of material depends on the type and shape of the material. If the piece has length L and cross-sectional area A, the resistance is
where Ρ is a constant (for a given material at a given temperature) known as the resistivity of the material.
Resistivity of the Object
Resistivity is the tendency of a material to behave as a resistor. You already know that not everything conducts electricity equally well, and that some materials (like copper) resist very little, while others (like rubber) provide enough resistance to effectively prevent the flow of current. Resistivity is a fundamental material property (like density or melting point), while the total resistance (R) depends on the material, the geometry, and the temperature.
Because the difference between Resistance and Resistivity can be difficult for students to remember, we can understand in a way:
- Resistance is the property of an object.
- Resistivity is the property of a material.
Resistivity is temperature dependent.
- For Conductors: As temperature increases, resistivity increases.
- For Semiconductors: As temperature increases, resistivity decreases.
Resistivities for some common materials at 20oC are:
|Ρ @ 20oC (Ω.m)
|1.6 x 10-8
|1.7 x 10-8
|2.4 x 10-8
|2.8 x 10-8
|6.9 x 10-7
|4.6 x 10-1
|6.4 x 102
|10 x 1010 - 10 x 1014
|100,000,000,000 - 1,000,000,000,000,000
|10 x 1013
|1.3 x 1016 - 3.3 x 1016
|13,000,000,000,000,000 - 33,000,000,000,000,000
Difference between Resistivity vs Difference Between Resistance
Difference Between Resistance vs Resistivity
Differences between Resistivity vs Difference Between Resistance
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