Answer
According to Maxwell, a changing electric field would produce a magnetic field perpendicular to the electric field. Therefore, it is impossible to have an electric wave without any magnetic component.
Work Step by Step
Maxwell showed that a changing electric field produces a magnetic field. If there is an electric wave, then the magnitude of the electric field would be changing continuously as the wave propagates. According to Maxwell, this changing electric field would produce a magnetic field perpendicular to the electric field. Therefore, it is impossible to have an electric wave without any magnetic component.
