Difference Between Resistance And Resistivity
Last Updated : 15 May, 2024
Understanding how electricity travels through materials is crucial in electronics and physics. Resistance and resistivity are key terms often confused, yet they describe different aspects of electrical conduction. Resistance measures how much an object hinders electric current, while resistivity reflects the inherent ability of the material itself to resist current.
This article clarifies the differences between these two fundamental concepts, highlighting their importance and impact on electrical systems.
What is Resistance?
Resistance is the property of a substance or component that opposes the flow of electric current through it is known as resistance. It is measured in ohms and is represented by the letter "R." Resistance is induced by a variety of factors, including material type, temperature, and material dimensions. When an electric current passes through a material, it encounters resistance, which causes energy to be dissipated in the form of heat.
Resistance Formula:
Resistance (R) = Voltage (V) / Current (I)
Resistance is directly proportional to the length and temperature while it is inversely proportional to the cross-sectional area of the material. It is measured in ohms (Ω). The higher the resistance, the more difficult it is for current to flow through the material. Resistance is calculated using Ohm's Law.
What is Resistivity?
Resistivity is defined as the resistance of a substance per unit length for a unit cross-section. The conductor's resistivity is only proportional to its temperature. It also depends on the nature of the conductor's substance. The ohmmeter is the SI unit of resistance. Temperature increases resistivity linearly. In comparison to insulator resistivity, conductor resistivity is low.
Resistivity Formula:
Resistivity (ρ) = Resistance (R) x Cross-sectional area (A) / Length (L)
Note: Several factors influence a material's resistivity, including its composition, temperature, and contaminants. Insulators, for example, have a larger resistance to the flow of electric current than metals, which have a low resistivity. This is because insulators have fewer free electrons than metals.
Difference Between Evaporation and Condensation
Basics | Resistance | Resistivity |
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| Definition | The measure of the degree to which an object opposes the flow of electric current through it. | The inherent property of a material determines how easily it can conduct electric current. |
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| Symbol | R | ρ (rho) |
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| Unit | Ohms (Ω) | Ohm-meters (Ω·m) |
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| Formula | R = V/I (where V is voltage and I is current) | ρ = RA/L (where R is resistance, A is the cross-sectional area, and L is length) |
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| Characterization | Resistance is a macroscopic property and depends on the size, shape, and material of an object. | Resistivity is a microscopic property and depends only on the material of an object. |
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| Temperature dependence | Resistance generally increases with an increase in temperature. | Resistivity generally increases with an increase in temperature. |
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| Importance | Resistance is important in determining the behavior of electrical circuits and devices. | Resistivity is important in designing electrical conductors and insulators. |
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| Materials | Resistance varies greatly among different materials. | Resistivity is a specific property of each material. |
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| Examples | Examples of objects with resistance include wires, resistors, and light bulbs. | Examples of materials with high resistivity include rubber, glass, and air. |
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| Measurement | Resistance can be measured using a multimeter. | Resistivity is usually measured by performing experiments on a sample of the material. |
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| Application | Resistance is important in designing electronic circuits and devices. | Resistivity is important in designing electrical conductors and insulators. |
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Similarities Between Resistance and Resistivity
Apart from differences, there are many similarities b/w resistance and resistivity such as:
- Resistance and resistivity are material physical qualities that characterize their ability to resist the flow of electrical current.
- Resistance and resistivity are both measured in ohms (Ω) in the International System of Units (SI).
- Temperature, composition, and dimensions of the material all have an impact on resistance and resistivity.
- Both resistance and resistivity are crucial in the design and study of electrical circuits and devices.
- Resistance and resistivity can both be used to calculate how much power a device dissipates as well as the voltage drop across it.