Question

Which expression gives the speed of electromagnetic waves in free space?

Options

• \[c=\frac{1}{\sqrt{\mu_0\varepsilon_0}}=3\times10^8\,\mathrm{m/s}\]

• \[c=\frac{\mu_0}{\varepsilon_0}=3\times10^8\,\mathrm{m/s}\]

• \[c=\sqrt{\mu_0\varepsilon_0}=3\times10^8\,\mathrm{m/s}\]

• \[c=\frac{1}{\mu_0\varepsilon_0}=3\times10^8\,\mathrm{m/s}\]

Answer 1

In free space, the speed depends on vacuum permeability and permittivity through \[c=\frac{1}{\sqrt{\mu_0\varepsilon_0}}\]. Its value is \[3\times10^8\,\mathrm{m/s}\].