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)

As, displacement current,
$I_d={\epsilon }_0\frac{d\varphi }{dt}...\left(i\right)$
Where, $\varphi =$ electric flux
$\because \varphi =E.A$
For area, $A=$ constant
$\therefore d\varphi =AdE...\left(ii\right)$
From Eqs. $\left(i\right)$ and $\left(ii\right)$, we get $I_d={\epsilon }_{0}A\frac{dE}{dt}$
So, time varying electric field generates the displacement current