Find the amplitude of the electric field in a parallel beam of light of intensity $2\: W/m^2$

Question

$\begin {array} {1 1} (a)\;388\: N/C & \quad (b)\;3.88\: N/C \\ (c)\;38.8\: N/C & \quad (d)\;0.388\: N/C \end {array}$