What is the range of frequency of $EM$ waves that are reflected back by the ionosphere?

The biological importance of the ozone layer is that:

If the electric field of a plane electromagnetic wave is $E_z = 60 \sin(0.5 \times 10^3 x + 1.5 \times 10^{11} t) \ Vm^{-1}$,then the magnetic field of the wave is

$A$ plane electromagnetic wave of wave intensity $6 \ W/m^2$ strikes a small mirror of area $40 \ cm^2$,held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be:

$A$ plane electromagnetic wave propagating along the y-direction can have the following pair of electric field $(\vec{E})$ and magnetic field $(\vec{B})$ components.

For a plane electromagnetic wave,$E_x = 0$,$E_y = 2.5 \frac{N}{C} \cos \left[ (2\pi \times 10^6 \frac{rad}{s})t - (\pi \times 10^{-2} \frac{rad}{m})x \right]$,and $E_z = 0$. Which of the following is true?