Discussion :: Exam Questions Paper
-
The inconsistency of Ampere's law can be removed by adding __________ to it.
A.
displacement current density alone.
|
B.
conduction current density alone.
|
C.
displacement and conduction current densities.
|
D.
none of these
|
Answer : Option A
Explanation :
The ampere's law is given as
∇.H = J
Taking divergence on both sides
∇.(∇xH) = ∇.J
i.e., ∇.(∇xH) = ∇.J = 0
∴ divergence of curl is always zero
But ∇.J = -rv ... continuity equation.
Hence the inconsistency. It can be removed as follows
→
Let ∇ x H = J + G where G is some unknown quality.
Then ∇.(∇ x H) = ∇.(J x G) = 0
i.e. ∇.J + ∇.G = 0
i.e. ∇.J = -∇.G
or ∇.G = (-rv)
i.e. ∇.G = rv ...... Gauss's law in point form
Differentiating on both sides.
∇.D = rv
Comparing (i) and (ii), G = D
Thus ∇ x H = J + D
Where J is conduction current density and D is displacement current density which is added to remove the inconsistency of Ampere's law.
Be The First To Comment