4) It is known that the area of the plate capacitor is S, the distance is D, and the dielectric constant of the medium is ɛ. The voltage between plates is u(t). Try to find the displacement current ip and the conduction current ic flowing through the capacitor, and explain the relationship betweer them. This shows what principle the full current should meet in the time-varying electromagnetic field.

4) It is known that the area of the plate capacitor is S, the distance is D, and the dielectric constant of the medium is ɛ. The voltage between plates is u(t). Try to find the displacement current ip and the conduction current ic flowing through the capacitor, and explain the relationship betweer them. This shows what principle the full current should meet in the time-varying electromagnetic field.