2.16 (a) Show that the normal component of the electrostatic field has a discontinuity from one side of a charged surface to another given by

whereis a unit vector normal to the surface at a point and σ is the surface charge density at that point. (The direction ofis from side 1 to side 2.) Hence, show that just outside a conductor, the electric field is σ/ε0.

(b) Show that the tangential component of the electrostatic field is continuous from one side of a charged surface to another.
[Hint: For (a), use Gauss’s law. For, (b) use the fact that work done by the electrostatic field on a closed loop is zero.]

 

Electric field on one side or a charged body Is Ei and electric field on the other side of the same body is E2. If infinite plane charged body has a uniform thickness, then electric field due to one surface of the charged body Is given by,

E¯1=σ2ϵ0n^                  ...i

Where,

n^ = Unit vector normal to the surface at a point a Surface charge
density at that point.

Electric field due to the other surface of the charged body,

E2=σ2ϵ0n^                       ...ii

Electric field at any point due to the two Surfaces,

E2¯E1¯=σ2ϵ0n^+σ2ϵ0n^=σϵ0n^(E2E1)n=σϵ9

Since inside a closed conductor, E=0,

E=E2=σ2ϵ0n^

Therefore, the electric field just outside the conductor is σϵnn^.

(b) When a charged particle is moved from one point to the other on a closed-loop, the work done by the electrostatic field is zero. Hence, the tangential component of the electrostatic field is continuous from one side of a charged surface to the other.