Answer: The amplitude is 0. (assuming that the amplitude ot both initial waves is the same)
Explanation:
When two monochromatic light waves of the same wavelength and same amplitude undergo destructive interference, means that the peak of one of the waves coincides with the trough of the other, so the waves "cancel" each other in that point in space.
Then if two light waves undergo destructive interference, the amplitude of the resultant wave in that particular point is 0.
That is called a physical trainer or a fitness coach. Hope I helped!
