What formula do I even use to solve this. Help!

Current Attempt in Progress The amplitude of the electric field component of an electromagnetic wave is increased from E to 3E. What is the corresponding change in the intensity of the wave? The intensity is unchanged by the increase in E. The intensity increases by a factor of nine. O The intensity increases by a factor of three. O The intensity decreases by a factor of three. O The intensity decreases by a factor of nine. Save for Later Attempts: 0 of 5 used Submit Answer SUPPORT