Dimension of $\frac{1}{\mu_0 \varepsilon_0}$ should be equal to

Electromagnetic waves are:

What is the value of the speed of light in free space?

The electric field of a plane electromagnetic wave propagating along the $x$-direction in vacuum is $\overrightarrow{E} = E_{0} \hat{j} \cos(\omega t - kx)$. The magnetic field $\overrightarrow{B}$ at the moment $t = 0$ is:

The energy associated with the electric field is $(U_E)$ and with the magnetic field is $(U_B)$ for an electromagnetic wave in free space. Then

The energy density of an electromagnetic wave in a vacuum is given by the relation: