Consider the following statements regarding Boundary Conditions:1.Tangential component of electric field is continuous across boundary.2.Normal component of electric flux density depends on surface charge density.3.Tangential component of magnetic field is discontinuous if surface current exists.4.Boundary conditions are independent of material properties.Which of the above statements is/are correct?

Correct Answer: B - 1, 2 and 3 only

Quick Concept Explanation

Electromagnetic boundary conditions come from Maxwell’s integral equations applied to an infinitesimal loop or pillbox at an interface. They tell you which field components are continuous and which can jump because of surface sources. Key relation: n×(E2−E1)=0 (standard no magnetic surface current); n·(D2−D1)=ρs; n×(H2−H1)=K; n·(B2−B1)=0.

Exam focus: Surface charge affects normal D; surface current affects tangential H. Common trap: Mixing E/D and H/B continuity conditions.

Statement-wise Verification

• Statement 1 - Correct.
  Tangential component of electric field is continuous across boundary.
  In the standard interface model without magnetic surface current: the tangential component of E is continuous across the boundary.
• Statement 2 - Correct.
  Normal component of electric flux density depends on surface charge density.
  The jump in normal electric flux density equals free surface charge density, n·(D2−D1)=ρs.
• Statement 3 - Correct.
  Tangential component of magnetic field is discontinuous if surface current exists.
  A surface current density K creates a discontinuity in tangential H, n×(H2−H1)=K.
• Statement 4 - Incorrect.
  Boundary conditions are independent of material properties.
  D=εE and B=μH, so ε and μ of the two media affect field-component relationships even when the fundamental boundary equations are applied.

Core Concept

Electromagnetic boundary conditions come from Maxwell’s integral equations applied to an infinitesimal loop or pillbox at an interface. They tell you which field components are continuous and which can jump because of surface sources.

Formula / Key Relationship

n×(E2−E1)=0 (standard no magnetic surface current); n·(D2−D1)=ρs; n×(H2−H1)=K; n·(B2−B1)=0.

Step-by-Step Check

Equations directly validate 1–3 and contradict the claim that boundary behavior is independent of materials. Hence B.

Why the Other Options Are Wrong

Option A is incorrect because it includes incorrect statement(s) 4 and omits correct statement(s) 2, 3. Option C is incorrect because it omits correct statement(s) 1. Option D is incorrect because it includes incorrect statement(s) 4.

Answer-Key Verification Note

The uploaded provisional key marks D . After independent technical verification, the defensible answer is B . This discrepancy is stated explicitly rather than silently copying the provisional key.

Exam Shortcut / Approach

Surface charge affects normal D; surface current affects tangential H.

Common Mistake

Mixing E/D and H/B continuity conditions.

Quick Revision

Electric and Magnetic Boundary Conditions is linked with EM Field Interfaces, Boundary Conditions and Electromagnetic Fields. Surface charge affects normal D; surface current affects tangential H.