Question

Displacement current is given by ______.

विकल्प

• `epsilon_0`

• `epsilon_0 ("d"phi_"E")/"dt"`

• `("d"phi_"E")/"dt"`

• `epsilon_0 ("d"^2phi_"E")/"dt"^2`

Answer 1

Displacement current is given by `underline(epsilon_0 ("d"phi_"E")/"dt")`.

Explanation:

Maxwell realized that the changing electric flux must be associated with a magnetic field. For example, for a parallel-plate capacitor:

`"E" = "V"/"d", "V" = "Q"/"C" and "C" = (epsilon_0"A")/"d"`

`=> "E" = "Q"/(((epsilon_0"A")/"d")"d") = "Q"/(epsilon_0 "A")`

Now, `phi_"E" = "EA" = "Q"/epsilon_o`

and displacement current, i_d = `"dQ"/"dt"`

Therefore, `"i"_"d" = epsilon_0 ("d"phi_"E")/"dt"`