Question

Displacement current is caused due to

• A. a time varying electric filed
• B. a constant electric field
• C. free electrons flow
• D. all of the above

Answer 1

Answer: (A)

a time varying electric filed

Answer 2

As, displacement current,
$I_{d} = \varepsilon_{0} \frac{d\phi}{dt} \quad...\left(i\right)$
Where, $\phi =$ electric flux
$\because \phi = E . A$
For area, $A =$ constant
$\therefore d\phi = A \,dE \quad...\left(ii\right)$
From Eqs. $\left(i\right)$ and $\left(ii\right)$, we get $I_{d} = \varepsilon_{0}A \frac{dE}{dt}$
So, time varying electric field generates the displacement current