In electromagnetism, electric flux is the measure of the electric field through a given surface, although an electric field in itself cannot flow. It is a way of describing the electric field strength at any distance from the charge causing the field.
The electric field E can exert a force on an electric charge at any point in space. The electric field is the gradient of the potential.
1) Why is the electric field 0 at the bottom of Gaussian surface? Isn't the electric field on both sides of the surface, pointing down and outwards like a plane of charge? see image.
2) Why does a charge distribution with cylindrical symmetry have to be infinitely long?
3) My book says a...
I am confused at this calculation of the electric flux through a trapezoidal surface. The flux in should equal the flux out.
The flux in equals -E*A1 where A1 is the area of the bottom of the trapezoid. The flux out equals E*A2 where A2 is the area of the top of the trapezoid. But the two fluxes...
1)Field Lines is supposed to represent the electric field around a charge ,now we can draw infinite field lines around a charge and sinc Electric flux is No of Field Lines /area ,does it become infinite ,the whole concept of field lines is quite in the Gray Area for me ,I can in theory mark...
$$\phi_E=\dfrac{Q_{\textrm{enclosed}}}{\varepsilon_0}\Rightarrow Q_{\textrm{enclosed}}=9,6\cdot 10^{-7}\, \textrm{C}$$
$$Q_{\textrm{enclosed}}=\sigma S=\sigma \pi R^2\Rightarrow \sigma =\dfrac{Q_{\textrm{enclosed}}}{\pi (0,1^2)}=3,04\cdot 10^{-5}\, \textrm{C}/\textrm{m}^2$$
I have a lot of...
Hi guys i have some concept issues about flux. My book says flux is proportional to the number of lines passing through that area. so my question is: first i am thinking that a 2D circle which has a 2r diameter and it is enclosing a 2q charge so its flux should be 2q/Epsilon.then i am thinking a...
I have tried to understand the solution given in the book which is as pasted below. The solution uses Gauss's Law but makes no mention of which Gaussian surface is used. The diagram that I have used to understand this problem is also given at the end. From the diagram, faces OADG, OABE and OEFG...
Phi= int(E.da) through a surface S
is a measure of “number of field lines” passing through S. I put this in quotes because of course we can only draw a representative sample of field lines. The total number would be infinite. But for a given sampling rate the flux is proportional to the number...
In this page you can see it’s written: E must be perpendicular to the surface. If it were not then the charges would move due to a component along the surface.
I am assuming the field is generated due to the charges on the surface.
I have a doubt. Is the author saying if it were not...
When I look at this question, I can see two possible values of electric flux depending on how I take the normal area vector for either ends ##A \text{ and } A^{'}##.
What is wrong with my logic below where I am ending up with two possible answers? The book mentions that only ##2E\Delta{S}## is...
Let's say I place a positive point charge inside a hollow conducting sphere. If we take a Gaussian surface through the material of the conductor, we know the field inside the material of the conductor is 0, which implies that there is a -ve charge on the inner wall to make the net enclosed...
Homework Statement
Griffiths' Introduction to Electrodynamics problem 2.10,
Homework Equations
Gauss' Law, ##\int_{S} \textbf{E}\cdot \textbf{dS} = \frac{Q_{\text{enc}}}{\epsilon_0}##[/B]
The Attempt at a Solution
It seems reasonable that the flux through the shaded surface and the...
Say you have a hollow cylinder, whose one side is open. Now, you pace a positive charge ##Q## at the centre of this open end (such that it is just inside the cylinder). How much should be the flux coming out from the closed end?
I just thought of this problem. In order to use Gauss' Law, we...
Homework Statement
A charged, straight line/rod of infinite length has a Discrete uniform distribution of charge, has a linear density of λ and is at a distance d from a sphere with a radius of R.
Find the entirety of the Electrical Flux that is caused by this charged rod, which passes...
Homework Statement
In (Figure 1) take the half-cylinder's radius and length to be 3.4 cm and 15 cm, respectively.
If the electric field has magnitude 5.3 kN/C, find the flux through the open half-cylinder. The surface here is the right half of the surface of a full cylinder. The surface does...
Homework Statement
A circle, centered on the origin, has a radius of 1 mm. At each "pole" (1,0), (0,-1), (-1,0), (0,1) is an electric dipole. The positive charge of +10 microCoulombs is inside the circle, the negative charge of -10 microCoulombs is just outside the circle.
What is the...
At this point I was given rho, sigma and landa to hold value of these three different kinds of density
ρ = Charge/Volume -------------- Volume Density
σ = Charge/Area ----------------- Area Density
λ = Charge/Length ---------------- Length Density
How do I know which type of density to use over...
Homework Statement
I need help in figuring out if I have done this problem correctly. From what I understand ∫E * dA = E*A, where E is the electric field and A is the area of a side. My biggest concern is if I can plug in the length "L" for the "x" and "z" variables within "E = -5x * E0/L i +...
Homework Statement
Hello,
A 3.60cm x 4.50cm rectangle lies in the xy-plane. What is the electric flux through the rectangle if E=(80.0i + 50k) N/C ?
Homework Equations
Φ = E * A =EAcos(θ)
The Attempt at a Solution
My attempt:
First convert the rectangle units from cm to m.
4.50cm =...
Hello,
The problem:
A 3.60cm x 4.50cm rectangle lies in the xy-plane. What is the electric flux through the rectangle if E=(80.0i + 50k) N/C ?
My attempt:
First convert the rectangle units from cm to m.
4.50cm = 0.045m
3.60cm = 0.036m
Find the area of the rectangle.
A = 0.036m x 0.045m =...
Homework Statement
Two hemispherical surfaces, 1 and 2, of respective radii r1 and r2, are centered at a point charge and are facing each other so that their edges define an annular ring (surface 3), as shown.
Homework Equations
The field at position r⃗ due to the point charge is:
E⃗ (r⃗...
Homework Statement
A long straight wire has a line charge, λ that varies in time according to: λ = λ0e(-βt). A square loop of dimension, a, is adjacent to the wire (at a distance a away from the wire). Calculate expressions for the displacement current at the center of the wire loop and the...
Why doesn't the flux through a Gaussian surface change, when the shape is changed? (while keeping the net charge inside it the same)
Flux is the dot product of electric field and surface area, so wouldn't it change if surface area is changed?
When we looked at some closed surface, we defined the overall electric flux of that surface as the sum of all infinitesimal fluxes of all the infinitesimal surfaces that make the quoted closed surface. Does that change if we do not have a closed surface, but a rigid body such as, let's say, a...
Homework Statement
A slab of insulating material has thickness 2d and is oriented so that its faces are parallel to the yz-plane and given by the planes x=d and x=−d. The y- and z-dimensions of the slab are very large compared to d and may be treated as essentially infinite. Let the charge...
Homework Statement
In a region of space there is an electric field E(vector E) that is in the x-direction and that has magnitude E=(663 N/(C*m))x
Find flux for this field through a square in xy plane at z=0 and with side length 0.330m . One side of the square is along the +x-axis and another...
Homework Statement
1)
A large cube has its bottom face on the x-z plane and its back face on the x-y plane. The corners on the x-axis are at (3.39 m,0,0) and (12.3 m,0,0). The cube is immersed in an electric field pointing in the positive x-direction, and given by:
E = (91.2x^2 - 2.9)i, x is...
Homework Statement
The electric field has been measured to be horizontal and to the right everywhere on the closed box shown in the figure. All over the left side of the box E1 = 80 V/m, and all over the right, slanting, side of the box E2 = 400 V/m. On the top the average field is E3 = 260...
Homework Statement
The Earth possesses an electric field of (average) magnitude 150 N/C near its surface. The field points radially inward. Calculate the net electric flux outward through a spherical surface surrounding, and just beyond, the Earth's surface.
Homework Equations
Flux =...
Homework Statement
Assume I want to calculate the electric flux through a spherical surface centred at point P with radius R which contains a point charge Q, that is not concentric with the spherical surface.
Here, I can no longer assume that ∫∫sEdA = E.A, and I have to calculate the value of...
Hey there...
As far as I know, electric flux is a scalar quantity which means that negative values are smaller than zero. This concept really confuses me since most of the exercises I dealt with suggest that negative flux somehow is larger than zero flux
Example 1
the uniform field is directed...
Homework Statement
A spherical charge distribution is given by p = p_0 (1- \frac{r^2}{a^2}), r\leq a and p = 0, r \gt a , where a is the radius of the sphere.
Find the electric field intensity inside the charge distribution.
Well I thought I found the answer until I looked at the back of...
Homework Statement
I need to create an equation that can tell me the electric flux through the surface of a sphere (centered at the origin) due to a point charge placed at various locations in/around the sphere. For example, find the electric flux through the sphere (of radius = 1) with a point...