# Optics interference basic

1. Oct 16, 2009

### prashantgolu

why do we see 2waves when we consider interference ????why not three or four????eg when we find out conditions formaxima we look for condition when 2 waves interefere...why not 3????

2. Oct 16, 2009

### Staff: Mentor

It's certainly possible to consider more than two waves interfering. In my optics course I cover examples such as multiple-slit interference. And any diffraction situation (e.g. single-slit diffraction) is basically an infinite number of waves superposing together, which you analyze by integration rather than by simple addition.

3. Oct 16, 2009

### prashantgolu

what i meant is that we calculate the condition for maxima by taking 2 waves interefering but if we do by 3 waves then surely answer will be different...so why do we do by taking 2 waves

4. Oct 16, 2009

### Redbelly98

Staff Emeritus
It depends on the situation. If there are 2 waves present, we calculate using 2 waves. If 3 waves are present, we must use all 3 waves.

If you are referring to physics homework problems, we use 2 waves because that is easier to calculate and we want you to learn the basic principle by doing simpler calculations.

5. Oct 17, 2009

### prashantgolu

sorry i couldnt get you people to make it simple i was saying that we find net intensity at a point by finding net intensity between 2 waves why not threee why are we breaking waves in pairs why not in 3 waves in a group?

6. Oct 17, 2009