The orientation of the portable radio with respect to broadcasting station is important because the electromagnetic waves are plane polarised, so the receiving antenna should be parallel to the vibration of the electric or magnetic field of the wave.

Microwave oven heats up the food items containing water molecules most efficiently because the frequency of microwaves matches the resonant frequency of water molecules.

The displacement current through the capacitor is,

$$I_d=I_c=\frac{d q}{d t}\quad\text{... (i)}$$

Here, $$\quad q=q_0 \cos 2 \pi v t \text { (given) }$$

Putting this value in Eq (i), we get

$$\begin{aligned} & I_d=I_c=-q_0 \sin 2 \pi v t \times 2 \pi v \\ & I_d=I_c=-2 \pi v q_0 \sin 2 \pi v t \end{aligned}$$

$$\begin{aligned} & \text { Capacitive reaction } X_c=\frac{1}{2 \pi f C} \\ & \therefore \quad X_c \propto \frac{1}{f} \end{aligned}$$

As frequency decreases, $X_{\mathrm{c}}$ increases and the conduction current is inversely proportional to $X_c\left(\because I \propto \frac{1}{X_c}\right)$.

So, displacement current decreases as the conduction current is equal to the displacement current.

Magnetic field $\mathbf{B}=B_0$ sin $\omega t$

Given, equation $B=12 \times 10^{-8} \sin \left(1.20 \times 10^7 z-3.60 \times 10^{15} t\right) \mathrm{T}$.

On comparing this equation with standard equation, we get

$$B_0=12 \times 10^{-8}$$

The average intensity of the beam $I_{\mathrm{av}}=\frac{1}{2} \frac{B_0^2}{\alpha_0} \cdot c=\frac{1}{2} \times \frac{\left(12 \times 10^{-8}\right)^2 \times 3 \times 10^8}{4 \pi \times 10^{-7}}$

$$=1.71 \mathrm{~W} / \mathrm{m}^2$$