Difference Between Resistance And Resistivity

Difference Between Resistance And Resistivity: Every object provides some resistance to the flow of electric current. Resistance is the physical property of a substance because of which it opposes the flow of current i.e., electrons. and resistivity is the physical property of a particular substance that has dimensions. The property of resistance is used in several places like heaters, fuses, sensors, etc. Electrical resistivity measurement is used as a quality control test for calcareous soil.

Ohm’s law describes the link between resistance, resistivity, and material dimensions, stating that a material’s resistance is directly proportional to its resistivity and length, and inversely proportional to its cross-sectional area. This means that for a given material, the longer the length, the greater the resistance; and the larger the cross-sectional area, the lower the resistance.

What is Resistance?

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 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.

Formula:

Resistance (R) = Voltage (V) / Current (I)

Where, 

R is resistance in ohms, 

V is voltage in volts, 

and I represent current in amperes.

Example:

If a resistor has a voltage drop of 5 volts and a current of 2 amperes flowing through it, then the resistance of the resistor can be calculated as follows:

R = V / I 

= 5 V / 2 A 

= 2.5 Ω

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.

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.

Formula:

Resistivity (ρ) = Resistance (R) x Cross-sectional area (A) / Length (L)

where ρ is the resistivity in ohm meters,

R is resistance in ohms, 

A is the cross-sectional area in square meters, 

and L is the length in meters.

Example:

Copper has a resistivity of 1.68 x 10^-8 Ω•m at room temperature, which is much lower than that of steel (6.9 x 10^-7 Ω•m).Difference Between Resistance and Resistivity

	Resistance	Resistivity
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.
Symbol	R	ρ (rho)
Unit	Ohms (Ω)	Ohm-meters (Ω·m)
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)
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.
Temperature dependence	Resistance generally increases with an increase in temperature.	Resistivity generally increases with an increase in temperature.
Importance	Resistance is important in determining the behavior of electrical circuits and devices.	Resistivity is important in designing electrical conductors and insulators.
Materials	Resistance varies greatly among different materials.	Resistivity is a specific property of each material.
Examples	Examples of objects with resistance include wires, resistors, and light bulbs.	Examples of materials with high resistivity include rubber, glass, and air.
Measurement	Resistance can be measured using a multimeter.	Resistivity is usually measured by performing experiments on a sample of the material.
Application	Resistance is important in designing electronic circuits and devices.	Resistivity is important in designing electrical conductors and insulators.

Similarities Between Resistance and Resistivity

1. Resistance and resistivity are material physical qualities that characterize their ability to resist the flow of electrical current.
2. Resistance and resistivity are both measured in ohms (Ω) in the International System of Units (SI).
3. Temperature, composition, and dimensions of the material all have an impact on resistance and resistivity.
4. Both resistance and resistivity are crucial in the design and study of electrical circuits and devices.
5. Resistance and resistivity can both be used to calculate how much power a device dissipates as well as the voltage drop across it.

Conclusion

In summary, resistance is the physical property of a substance because of which it opposes the flow of current i.e., electrons. and resistivity is the physical property of a particular substance that has dimensions. The property of resistance is used in several places like heaters, fuses, sensors, etc. Electrical resistivity measurement is used as a quality control test for calcareous soil.

FAQs on Resistance and Resistivity

Que 1. What is resistance?

Ans- Resistance is a property of a material or device that opposes the flow of electrical current through. It is measured in ohms and depends on the physical dimensions of the material.

Que 2. What is resistivity?

Ans- Resistivity is defined as the material’s resistance per unit length for a unit cross-section. The ohmmeter is known for the SI unit of resistivity. 

Que 3. What is the difference between resistance and resistivity?

Ans- The main difference between resistance and resistivity is that resistance is dependent on the physical dimensions of a material, while resistivity is a fundamental property that is inherent to the material itself. Resistance is measured in ohms, while resistivity is measured in ohm meters.

Que 4. Which device is used to measure resistance?

Ans- Resistance can be measured using a multimeter it can be analog or digital.