Long-distance radio broadcasting uses which of the following waves?

The electromagnetic flux from the sun reaching the earth is $10^3 \, W/m^2$. The power incident on a roof of dimensions $8 \, m \times 20 \, m$ is ..... $W$.

If $\overrightarrow{E}$ and $\overrightarrow{B}$ represent electric and magnetic field vectors of an electromagnetic wave,the direction of propagation of the electromagnetic wave is along . . . . . . .

Which of the following is/are the property/properties of a monochromatic electromagnetic wave propagating in the free space?
$1$. Electric and magnetic fields will have a phase difference $\frac{\pi}{2}$.
$2$. The energy of the wave is distributed equally between electric and magnetic fields.
$3$. The pressure exerted by the wave is the product of its speed and energy density.
$4$. The speed of the wave is equal to the ratio of the magnetic field to the electric field.

The average power output of a point source of an electromagnetic radiation is $1080 \,W$. The maximum value of the rms value of the electric field at a distance of $3 \,m$ from the source is (in $\,Vm^{-1}$)

In vacuum,the speed of light depends upon