What is the dimension of $\frac{1}{\mu_0 \varepsilon_0}$? ($\mu_0 =$ magnetic permeability and $\varepsilon_0 =$ permittivity of free space)

$A$ plane electromagnetic wave of wavelength $3.0 \ m$ travels in vacuum along the positive $X$-axis. The electric field of amplitude $300 \ Vm^{-1}$ oscillates parallel to the $Y$-axis. Then the intensity of the wave is $(\mu_0 = 4\pi \times 10^{-7} \ Hm^{-1}, c = 3 \times 10^8 \ ms^{-1})$ (in $Wm^{-2}$)

In an electromagnetic wave,$E = 50 \sin(\omega t - kx)$. If $\mu = 4\mu_0$ and $\varepsilon = \varepsilon_0$,then the average power per unit area is $-$ (in $W/m^2$)

The average value of electric energy density in an electromagnetic wave is:

The sun delivers $10^{3} \,W m^{-2}$ of electromagnetic flux on the Earth's surface. The total power that is incident on a roof of dimensions $6 \,m \times 30 \,m$ is . . . . . . .

At an instant,a plane electromagnetic wave has its magnetic field in the direction of the vector $\hat{i}-\hat{j}$ and its electric field is in the direction of $\hat{i}+\hat{j}$. The wave is travelling along which direction?