Some queries on uniqueness theorem

Click For Summary
SUMMARY

The discussion centers on the Uniqueness Theorem in electrostatics, specifically regarding a solid conductor with a cavity containing a charge. It asserts that the distribution of induced charge on the cavity wall and the compensating charge on the outer surface is uniquely determined by the normal component of the electric field, expressed as σ = ε₀Eₙ. The electric field is derived from the electrostatic potential, which satisfies Poisson's equation, Δφ = -ρ/ε₀. The uniqueness theorem guarantees that given the charge configuration and boundary conditions, the solution for the potential and corresponding surface charges is unique.

PREREQUISITES
  • Understanding of electrostatics and electric fields
  • Familiarity with Poisson's equation and its applications
  • Knowledge of boundary conditions in electrostatic problems
  • Basic concepts of charge distribution in conductors
NEXT STEPS
  • Study the implications of the Uniqueness Theorem in electrostatics
  • Explore advanced applications of Poisson's equation in electrostatics
  • Investigate charge distribution in conductors with varying geometries
  • Learn about numerical methods for solving electrostatic problems
USEFUL FOR

Students and professionals in physics, electrical engineering, and anyone studying electrostatics or charge distribution in conductors.

VishweshM
Messages
2
Reaction score
0
Consider a solid conductor with a cavity inside. Place a charge well inside the cavity. The induced charge on the cavity wall and the compensating charge on the outer surface of the conductor will be distributed in a unique way. How does this follow from the Uniqueness Theorem of EM? David Griffith claims this but never gets around to explain it in his book. Any thoughts?
 
Physics news on Phys.org
All densities of charge are determined by the normal component of the electric field near the surface:
<br /> \sigma = \epsilon_0 E_n<br />

The electric field in turn is determined by the electrostatic potential \varphi(\mathbf x). This potential is a solution of Poisson's equation
<br /> \Delta \varphi = -\frac{\rho}{\epsilon_0},<br />
given the known charge inside the cavity and the boundary condition that potential is constant throughout the metal.

The uniqueness theorem states that the solution of this equation and conditions is unique. Since the potential determines everything, the surface charges are unique too.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 27 ·
Replies
27
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
4K