What is the path difference between two waves for constructive interfernce?

What is the path difference between two waves for destructive interference?

What is the path difference between two wave for destructive interference?

State the path difference between two waves for constructive interference .

The path difference between two waves is

State the path difference between two waves for destructive interference .

What is the path difference between the two waves the crest of the wave falls on the trough of the other?

What should be the path difference between two waves reaching a point for obtaining constructive interference in Young.s Double Slit experiment?

What is the path difference between the two waves,when the crest of one wave falls on the crest of the other?