The ratio of the electric field (E) and the magnetic field (B) associated with a plane electromagnetic wave is equal to

$ωk^{-1}$

The correct answer is Option (2) → $ωk^{-1}$

The ratio of the electric field ($E$) to the magnetic field ($B$) in a plane electromagnetic wave is given by:

$\frac{E}{B} = c$

We also know that the speed of light $c$ is related to angular frequency ($\omega$) and wave number ($k$) by:

$c = \frac{\omega}{k}$

Substituting this into the first equation gives:

$\frac{E}{B} = \frac{\omega}{k}$