The property which is not of an electromagnetic wave travelling in free space is that:

$A$ point light source emits electromagnetic ($E$.$M$.) waves in free space. $A$ detector, placed at a distance of $L \text{ m}$, measures the intensity as $I_o$. The detector is now shifted to another location on the same spherical surface, ensuring the angle between the original location and the new location is $45^{\circ}$. The measured intensity at the new location will be . . . . . . .

The figure shows the electric field $\overrightarrow{E}$ of an $EM$ wave at a certain point and a certain instant. The wave is transporting energy in the negative $z$ direction ($-z$ direction). What is the direction of the magnetic field $\overrightarrow{B}$ of the wave at that point and instant?

$A$ carbon dioxide laser emits a sinusoidal electromagnetic wave that travels in a vacuum in the negative $x-$ direction. The wavelength is $10.6\,\mu m$ and the $\vec E$ field is parallel to the $z-$ axis,with $E_{max} = 1.5 \times 10^6\, V/m$. Then the vector equations for $\vec E$ and $\vec B$ as a function of time and position are:

The ratio of contributions made by the electric field and magnetic field components to the intensity of an electromagnetic wave is

An electromagnetic wave of frequency $1 \times 10^{14} \,Hz$ is propagating along the $z$-axis. The amplitude of the electric field is $4 \,Vm^{-1}$. What is the energy density of the electric field? (Permittivity of free space $\varepsilon_0 = 8.8 \times 10^{-12} \,C^2 \,N^{-1} \,m^{-2}$)