Electric flux is the measure of number of electric field lines passing through a given area. The electric flux is determined by the number of electric field lines travelling through a virtual surface.
It’s worth noting that while charges outside the closed surface have no effect on the electric flux, charges outside the closed surface can have an impact on the net electric field, E, in the Gauss’ Law equation. While Gauss’ Law is true in all scenarios, it is only effective for “by hand” computations when the electric field has a high degree of symmetry. Spherical and cylindrical symmetry are two examples.
Volt meters (V m) or Newton meters squared per coulomb (N m2 C−1) are the SI units for electric flux. As a result, the SI base units for electric flux are kg·m3·s−3·A−1
What is an electric flux?
Faraday did a lot of experiments with the charged objects, and the field lines surrounding them. As a result of his studies, he concluded that a charge generates electric field lines around it in space, which are fixed in number around the charge.
Electric Flux is the measure of number of electric lines of force. It represents the vector flux density, enclosing a given volume. This quantity can be calculated based on the potential and charge of a point charge accumulating in a certain region and expressed as Φ.
Importance of an electric flux
We can safely say that electric flux has physical importance.
It determines the overall charge contained inside any given surface.
To create the more number of electric field lines, more charge must be present inside the closed surface.
Electric Flux Formula
The electric flux is the total number of electric field lines passing through a given area in a given amount of time. The total flux is provided as follows when the plane is normal to the field’s flow:
ϕp=EA
The electric flux is the total number of electric field lines passing through a given area in a given amount of time. If the plane is not normal to the flow of the electric field, then
ϕ=EAcosΘ
Where,
The electric field’s magnitude is denoted by the letter E.
Area of the plane is denoted by A.
The angle formed between the plane and the axis parallel to the direction of the electric field’s flow is denoted by the Ɵ symbol.
Electric Flux Density
The quantity of flux traveling through a unit surface area in a region imagined at right angles to the direction of the electric field is known as electric flux density. The formulation for the electric field at a given place is, E = Q/ 4 (π ϵ_o)r2.
Where, Q is the charge of the body by which the field is created. r is the distance of the point from the center of the charged body.
As, we know, Q = Ψ
Since 4πr2 is the surface area of the imaginary sphere of radius r, this is the formula for flux per unit area. This is the flux per unit area traveling through the charge at a distance of r from the center. This is referred to as the electric flux density at the specified place. It’s usually represented by the letter D in English. As a result of the aforementioned formula for D, it is evident that the electric field intensity and density are in phase.
Electric flux density is important to understand in the field of electromagnetism because it explains why some materials conduct while others insulate when a charge is placed upon them. Insulators don’t allow the electric charges to pass through their volume because electric flux density is 0 within their volume.
Electric flux and Gauss’s law
Multiplying the electric field by the surface area projected in a plane perpendicular to the field yields the electric flux through an area. Gauss’ Law is a general principle that may be used to calculate the area of any closed surface. It’s a valuable tool since it lets you estimate the amount of confined charge by mapping the field on a surface outside the charge distribution. For geometries with proper symmetry, it simplifies the computation of the electric field.
Imagine a probe with an area of A that can measure the electric field perpendicular to the region as another way to see this. Stepping across a closed surface and measuring the perpendicular field times the surface’s size provides an accurate measure of the total net electric charge within the surface, independent of how that charge structure is organized.
Every field line directed into a closed surface continues through the interior and is directed outward somewhere on the surface if there is no net charge within the surface. The negative flux merely matches the positive flux in magnitude, resulting in a net, or total, electric flux of zero.
Conclusion
Here we went through a detailed description of electric flux and a few of its essential aspects including its formula, density calculation and its importance. Make sure to understand the concept of Gauss’s law and electric flux thoroughly as it is an important part of the topic.
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