Velocity of electromagnetic waves in vacuum is given by:

$\sqrt{\mu_0 \varepsilon_0}$ $\sqrt{\frac{\mu_0}{\varepsilon_0}}$ $\sqrt{\frac{\varepsilon_0}{\mu_0}}$ $\frac{1}{\sqrt{\mu_0 \varepsilon_0}}$

$\frac{1}{\sqrt{\mu_0 \varepsilon_0}}$

The velocity of electromagnetic waves in free space (vacuum) is given by c = $\frac{1}{\sqrt{\mu_0 \varepsilon_0}}=3 \times 10^8 ms^{-1}$