What is the cause of the greenhouse effect?

An electromagnetic wave of intensity $50 \ W m^{-2}$ enters a medium of refractive index $n$ without any loss. The ratio of the magnitudes of electric fields and the ratio of the magnitudes of magnetic fields of the wave before and after entering the medium are respectively given by:

$A$ point source of $100\,W$ emits light with $5\%$ efficiency. At a distance of $5\,m$ from the source,the intensity produced by the electric field component is:

The electric field part of an electromagnetic wave in a medium is represented by $E_x = 0$; $E_y = 2.5 \frac{N}{C} \cos \left[ (2\pi \times 10^6 \frac{rad}{s})t - (\pi \times 10^{-2} \frac{rad}{m})x \right]$; $E_z = 0$. The wave is:

The electric field of a plane electromagnetic wave is given by $\overrightarrow{E} = E_{0}(\hat{x} + \hat{y}) \sin(kz - \omega t)$. Its magnetic field will be given by

If the magnetic field of a plane electromagnetic wave is given by $B = 5 \times 10^{-6} \sin (0.6 \times 10^2 x + 0.5 \times 10^{10} t)$,then the speed of the wave is