Solving Electric Field Boundary Conditions Across a Dipole Layer

Click For Summary
SUMMARY

The discussion focuses on determining the boundary conditions for the electric potential and electric field components across a dipole layer located at the plane x=0. It establishes that the potential is discontinuous due to the dipole layer's surface charge density, D(y,z), while the tangential components of the electric field (E_y and E_z) remain continuous. The normal component, E_x, experiences a discontinuity. The electric field components can be derived using the equations E_x = -d[phi]/dx, E_y = -d[phi]/dy, and E_z = -d[phi]/dz, with the discontinuity calculated using the surface charge density and permittivity ε0.

PREREQUISITES
  • Understanding of electric field boundary conditions
  • Familiarity with dipole layers and surface charge density
  • Knowledge of electric potential and its relationship to electric fields
  • Proficiency in calculus, specifically differentiation
NEXT STEPS
  • Review the derivation of electric field boundary conditions in electrostatics
  • Study the effects of surface charge density on electric fields
  • Learn about the implications of discontinuities in electric fields across boundaries
  • Explore practical applications of dipole layers in electrostatics
USEFUL FOR

Students and professionals in physics and electrical engineering, particularly those studying electrostatics, boundary value problems, and electric field analysis.

Norman
Messages
895
Reaction score
4
This is a homework question so please do not just tell me the answer, but please point me in the right direction.

A dipole layer, D(y,z), exists on the plane x=0. Find the boundary conditions (discontinuities, if any) for [phi](x,y,z), E_x(x,y,z),
E_y(x,y,z), and E_z(x,y,z) across the plane x=0. In view of this result do you believe in the boundary condition that the tangential component of E is contiuous across a boundary? Review the derivation of the boundary condition and see if and where the derivation breaks down.

When I read the first part of the problem I was content with how to solve it. The potential is discontinuous by D/[epsilon_0]. Then I would argue using typical boundary value knowledge that E_y and E_z are continuous and that E_x should be discontinuous. But after finishing reading the problem, it seems that my so called "notions" of the situation might be incorrect. Where do I start with finding the Electric Field components? I am very confused and any help would be very appreciated.
Cheers
 
Physics news on Phys.org


To solve this problem, you need to use the boundary conditions for electric fields. These conditions state that the tangential component of the electric field must be continuous across a boundary, while the normal component may have a discontinuity if there is a surface charge present.

In this case, the dipole layer introduces a surface charge density on the plane x=0. This means that there will be a discontinuity in the normal component of the electric field at this boundary. To find the electric field components, you can use the electric field equations:

E_x = -d[phi]/dx
E_y = -d[phi]/dy
E_z = -d[phi]/dz

Using these equations, you can determine the electric field components on either side of the boundary x=0. The discontinuity in the normal component of the electric field can be calculated using the surface charge density D(y,z) and the permittivity of the medium, ε0.

Regarding the belief in the boundary condition that the tangential component of the electric field is continuous, you can review the derivation of this boundary condition to see if and where it breaks down. One way to do this is to consider a simple case where there is no surface charge present (i.e. D(y,z)=0). In this case, the electric field should be continuous across the boundary x=0. From this, you can see if and where the derivation of the boundary condition breaks down.

Overall, to solve this problem, you need to use the boundary conditions for electric fields and the electric field equations. You can also review the derivation of the boundary condition to better understand its validity. I hope this helps point you in the right direction.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 25 ·
Replies
25
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
3
Views
1K
Replies
9
Views
739
Replies
7
Views
2K
Replies
1
Views
2K
Replies
1
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K