To heat the food containing water,the frequency of the microwaves used in a microwave oven is

$A$ plane electromagnetic wave is travelling in the positive $X$-axis. At the instant shown,the electric field at the extremely narrow dashed rectangle is in the $-ve$ $Z$-direction and its magnitude is increasing. Which diagram correctly shows the direction and relative magnitudes of the magnetic field at the edges of the rectangle?

The magnetic field in a travelling electromagnetic wave has a peak value of $20 \ nT$. The peak value of electric field strength is ...... $Vm^{-1}$.

For a radiation of $9 \text{ GHz}$ passing through air,the number of waves passing through $1 \text{ m}$ length is . . . . . . .

Identify the correct statements from the following descriptions of various properties of electromagnetic waves.
$A$. In a plane electromagnetic wave,the electric field and magnetic field must be perpendicular to each other,and the direction of propagation of the wave should be along the electric field or magnetic field.
$B$. The energy in an electromagnetic wave is divided equally between the electric and magnetic fields.
$C$. Both the electric field and magnetic field are parallel to each other and perpendicular to the direction of propagation of the wave.
$D$. The electric field,magnetic field,and direction of propagation of the wave must be mutually perpendicular to each other.
$E$. The ratio of the amplitude of the magnetic field $(B_0)$ to the amplitude of the electric field $(E_0)$ is equal to the reciprocal of the speed of light $(1/c)$.
Choose the most appropriate answer from the options given below:

Give the relation between vacuum permittivity $(\epsilon_{0})$, vacuum permeability $(\mu_{0})$, and the speed of light $(c)$.