Show that the dimensions of the displacement current are that of an electric current.
The displacement current Id is produced by a varying electric
field. It is given by the relation
where ϵ0 is the electric permittivity of free space(vacuum) and is
equal to 8.85 × 10-12 C2 N-1 m-2 and ϕE is the electric flux produced
by the time varying electric field.
To find the dimension of Id and check whether it is the same as that
of electric current, we need to find the dimension of .
We can simplify using Gauss’s Law. According to Gauss’s law
the electric flux ϕE through a surface is given as
Using the above relation, the displacement current becomes
The dimension of displacement current is the dimension of the
quantity in the R.H.S of the above equation
As [A] is the dimension of electric current so displacement current
has same dimension as that of electric current.