Question

what occurs when the trough of one light wave meets the trough of a second light wave?
wave destruction
constructive interference
wave building
destructive interference

Explanation:

When two wave troughs meet, they are in phase, leading to a combined wave with greater amplitude. This phenomenon is defined as constructive interference. The other terms either describe the opposite effect (destructive interference, which happens when a trough meets a crest) or are not standard scientific terms for this behavior.

Answer:

constructive interference