Does Kirchhoff's laws apply to AC circuits?

The magnetic field in a plane electromagnetic wave is ${\mathrm{B}}_{\mathrm{y}}=2\times {10}^{-7}\sin \left(0.5\times {10}^3\mathrm{x}+1.5\times {10}^{11}\mathrm{t}\right) \mathrm{Tesla}$. What is the wavelength and frequency of the wave?

A plain EM wave moving with a velocity $3\times {10}^8{\mathrm{ms}}^{-1}$has an electric field which oscillates sinusoidally with a frequency $2\times {10}^{12 }\mathrm{Hz}$ and amplitude $48 \mathrm{V}/\mathrm{m}$. What is the amplitude of the oscillating magnetic field?

Seawater at a frequency $f=9\times {10}^2 \mathrm{Hz}$, has permittivity $\epsilon =80{\epsilon }_0$ and resistivity $\rho =0.25 \mathrm{\Omega } \mathrm{m}$. Imagine a parallel plate capacitor is immersed in seawater and is driven by an alternating voltage source $V\left(t\right)=V_0\sin \left(2\pi ft\right)$. Then the conduction current density becomes ${10}^{\mathrm{x}}$ times the displacement current density after time $t=\frac{1}{800} \mathrm{s}.$ The value of $x$ is _______

(Given $\left.:\frac{1}{4\pi {\epsilon }_0}=9\times {10}^9 \mathrm{N} {\mathrm{m}}^2 {\mathrm{C}}^{-2}\right)$

Match the following and rewrite:

What is displacement current? Give the expression for it.