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Unit of Electric Flux - Definition, Formula, FAQS

Unit of Electric Flux - Definition, Formula, FAQS

Team Careers360Updated on 02 Jul 2025, 04:58 PM IST

In this article we are going to learn about Electric flux, S.I unit of electric flux, Electric flux density , Unit of electric flux density and many more.

Unit of Electric Flux - Definition, Formula, FAQS
Unit of Electric Flux

What is Electric Flux?

An electric field's property is electric flux.

It can be compared to the number of forces that cross a certain area.

Electric field lines are commonly thought to begin with positive charges and conclude with negative charges.

Negative field lines are those that are directed into a closed surface, whereas positive field lines are those that are directed out of a closed surface.
If no net charge exists within a closed surface, every field line directed into the surface passes through the interior and is usually directed outward elsewhere on the surface.

The negative flux just equals the positive flux in magnitude, resulting in a net or total electric flow of zero.

When a net charge is imprisoned inside a closed surface, the total flux through the surface is proportional to the enclosed charge, positive if the charge is positive and negative if the charge is negative.

Also read -

Gauss law

Formula shows Relation between electric flux and electric field

Gauss law for the electric field is the mathematical relationship between electric flux and the contained charge.

It's one of electromagnetism's fundamental rules.

The net flux of an electric field through any closed surface is usually equal to the enclosed charge, in coulombs, divided by a constant termed the permittivity of free space in the related meter-kilogram-second system and the International System of Units (SI).

The net flow of an electric field through any closed surface in the centimetre-gram-second system is equal to 4 times the contained charge, measured in electrostatic units (esu).

The number of electric field lines passing through a virtual surface determines the electric flux.

This can be explained using an equation.

The electric flux (ΦE)) travelling through a surface of vector area S if the electric field is homogeneous is:

ΦE = E⋅S = EScosθ,

where E is the electric field's magnitude (in units of V/m), S is the surface's area and is the angle between the electric field lines and the normal (perpendicular) to S.

The electric flux dΦE through a small surface area dS in a non-uniform electric field is commonly indicated by:

dΦE=E⋅dS,

where E denotes the electric field, and A denotes the area component perpendicular to the field.

Commonly Asked Questions

Q: What is electric flux and why is it important in physics?
A:
Electric flux is a measure of the electric field passing through a given surface area. It's important because it helps us understand how electric fields interact with surfaces and is crucial in applying Gauss's law to solve complex electrostatic problems. Electric flux provides insights into the strength and distribution of electric fields in space.
Q: Can electric flux be negative? If so, what does it mean?
A:
Yes, electric flux can be negative. A negative flux indicates that the electric field lines are entering the surface, rather than leaving it. The sign of the flux depends on the relative orientation of the electric field and the surface normal vector.
Q: How does the shape of a surface affect electric flux?
A:
The shape of a surface affects electric flux because flux depends on both the strength of the electric field and the area of the surface. A curved surface may have different amounts of flux passing through different parts, while a flat surface perpendicular to the field lines will have uniform flux across its area.
Q: Why is the concept of solid angle important in understanding electric flux?
A:
Solid angle is crucial because it helps us understand how electric flux varies with distance from a point charge. As we move farther from a point charge, the solid angle subtended by a surface decreases, which explains why the flux through the surface decreases with the square of the distance.
Q: How does the orientation of a surface relative to the electric field affect the flux through it?
A:
The orientation of the surface relative to the electric field is critical in determining the flux. Maximum flux occurs when the surface is perpendicular to the field lines. As the surface tilts, the flux decreases, becoming zero when the surface is parallel to the field lines.

SI unit of electric flux

Voltmeters (V m), which is also equivalent to newton-meters squared per coulomb, are the SI base unit of electric flux (N m2 C-1)

Furthermore, kg·m3·s-3·A-1.is the fundamental unit of electric flux.

We now know that (N m2 C-1) is the SI unit for electric flux.

M = MASS.
L = LENGTH.
T = TIME.
I = CURRENT

Related Topics Link,

As a result, we know that the SI unit of force ‘N/Newton' is represented in dimension as MLT−2

M 2 represents the SI unit of meter

Length is represented in dimension as L2 .
And ‘C’ the SI unit of charge is represented in dimension as M0 L 0 T 1 I 1 ,

As a result, the dimensional values are converted to the SI unit of electric flux. (N m2 C-1) we get, M·L3·T-3·I-1

Electric flux dimensional formula
Electric flux is a measure of the dispersion of the electric field through a specific surface in electromagnetism.

The electric flux dimensional formula is discussed earlier

[M L3 T−3 A−1]

Also Read:

Electric flux density

Electric flux density is the electric flux passing through a unit area perpendicular to the direction of the flux. Electric flux density is a measure of the strength of an electric field generated by a free electric charge.

Unit of electric flux density

Electric flux density is obtained by flux passing per unit area.

Unit of ϕ=Nm2/C

Unit of electric flux density=Nm2/C/m2=N/C

Conclusion

Electric flux is a scalar quantity

The SI unit of electric flux is (N m2 C-1)

The dimensional formula of electric flux is M·L3·T-3·I-1

Also, check-

NEET Highest Scoring Chapters & Topics
This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.
Download E-book

NCERT Physics Notes:

Commonly Asked Questions

Q: What is the SI unit of electric flux?
A:
The SI unit of electric flux is newton-meter squared per coulomb (N⋅m²/C) or volt-meter (V⋅m). This unit is derived from the definition of electric flux, which involves electric field strength (N/C or V/m) multiplied by area (m²).
Q: How is the unit of electric flux related to the units of electric field and area?
A:
The unit of electric flux is a product of the units of electric field and area. Electric field is measured in N/C or V/m, and area is measured in m². When multiplied, these give N⋅m²/C or V⋅m, which are the units of electric flux.
Q: What's the difference between electric flux and magnetic flux?
A:
While both are measures of field strength through an area, electric flux quantifies electric fields (measured in N/C or V/m) passing through a surface, while magnetic flux quantifies magnetic fields (measured in teslas) passing through a surface. Their units and the fields they describe are different.
Q: What's the significance of Gauss's law in electrostatics?
A:
Gauss's law is significant in electrostatics because it relates the electric flux through a closed surface to the enclosed charge. This allows us to calculate electric fields for symmetrical charge distributions without needing to use more complex methods like direct integration of Coulomb's law.
Q: What's the difference between electric flux density and electric flux?
A:
Electric flux density (D) is the amount of electric flux per unit area, measured in coulombs per square meter (C/m²). It's a vector quantity. Electric flux (Φ) is the total amount of electric field passing through a surface, measured in N⋅m²/C or V⋅m. Flux is the integral of flux density over an area.

Frequently Asked Questions (FAQs)

Q: How does the concept of electric flux relate to the boundary conditions of electric fields at interfaces?
A:
Electric flux is
Q: Can you have electric flux in a vacuum?
A:
Yes, you can have electric flux in a vacuum. Electric flux is a property of the electric field itself and doesn't require a medium. In fact, electric fields and flux often behave more simply in a vacuum because there are no complicating factors like polarization of materials.
Q: How does the concept of electric flux apply to Van de Graaff generators?
A:
In a Van de Graaff generator, the concept of electric flux helps explain charge accumulation. As charge is deposited on the dome, it spreads out to maximize the flux leaving the surface. This results in a high electric field near the dome's surface, especially at points and edges where the flux is concentrated, leading to the characteristic hair-raising effect.
Q: Why is the electric flux through any closed surface in electrostatics always an integer multiple of 1/ε₀?
A:
According to Gauss's law, the electric flux through any closed surface is equal to the enclosed charge divided by the permittivity of free space (ε₀). Since charge is quantized in multiples of the elementary charge e, the flux must always be an integer multiple of e/ε₀. This fundamental relationship links the quantization of charge to the continuous nature of electric fields.
Q: How does the concept of electric flux apply to electrostatic shielding?
A:
Electrostatic shielding works on the principle that electric flux cannot penetrate a conductor. When a conductor completely encloses a region, no external electric flux can enter that region. This is why Faraday cages are effective at shielding: they redirect the electric flux around the enclosed space, creating a field-free region inside.
Q: How does the concept of electric flux relate to the principle of superposition in electrostatics?
A:
The principle of superposition states that the total electric field at a point due to multiple charges is the vector sum of the fields due to individual charges. This principle extends to electric flux: the total flux through a surface due to multiple charges is the sum of the fluxes due to each charge individually. This additive property of flux is crucial in applying Gauss's law to complex charge distributions.
Q: How does the concept of electric flux relate to the behavior of electric fields at sharp points?
A:
The concept of electric flux helps explain the high field strength near sharp points of conductors. As the surface area decreases near a point, the same amount of flux must pass through a smaller area, resulting in a higher flux density and thus a stronger electric field. This is why sharp points on conductors are often sites of electric discharge.
Q: How does the concept of electric flux apply to the design of electrical insulators?
A:
In designing electrical insulators, understanding electric flux is crucial. Good insulators minimize electric flux through their volume, redirecting field lines around them. The shape of insulators is often designed to spread out the flux over a larger surface area, reducing the local field strength and preventing breakdown. This is why high-voltage insulators often have a complex shape with multiple sheds or fins.
Q: Can electric flux be used to explain the concept of electric field lines?
A:
Yes, electric flux is closely related to the concept of electric field lines. Field lines can be thought of as representing the direction of electric flux. The density of field lines passing through a surface is proportional to the flux through that surface. This visualization helps in understanding the strength and direction of electric fields in space.
Q: Why is the electric flux through a closed surface containing no charges always zero?
A:
The electric flux through a closed surface containing no charges is always zero because, according to Gauss's law, the net flux is proportional to the enclosed charge. With no enclosed charge, there's no net outward or inward flux; any field lines entering the surface must exit it, resulting in zero net flux.
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