Q 12-08-041JEE MainJEE Main 2025 (22 Jan, Shift 2)Easy
A parallel plate capacitor of area $A = 16\ \text{cm}^2$ and separation between the plates $10\ \text{cm}$ is charged by a DC current. Consider a hypothetical plane surface of area $A_0 = 3.2\ \text{cm}^2$ inside the capacitor and parallel to the plates. At an instant, the current through the circuit is $6\ \text{A}$. At the same instant the displacement current through $A_0$ is ______ mA.
Numerical value type. Enter your answer.
Answer: 1200
The displacement current between the plates equals the conduction current, $6\ \text{A}$, and is spread uniformly over the plate area (uniform field). Through the smaller surface:
$$I_d = I\cdot\frac{A_0}{A} = 6\times\frac{3.2}{16} = 1.2\ \text{A} = 1200\ \text{mA}$$
Solution by Sreeraj P, M.Sc Physics