Answer:
Constructive interference
Step-by-step explanation:
The superposition of two wave is called interference phenomenon. After interference of wave, the amplitude of resultant wave can be more, less or remains the same.
The two conditions of interference are :
1. Constructive interference 2. Destructive interference
According to given question, when the trough of wave A overlaps the trough of wave B constructive interference occurs. The amplitude of resultant wave is greater than the individual waves. Also, the energy of the resultant wave is more than the energies of wave A and wave B.