Question

Two incoherent sources of light emitting light of intensity `I_(0)` and `3I_(0)` interfere in a medium. Calculate, the resultant intensity at any point.

Answer 1

Since, the two sources are incoherent, hence we do not obtain any sustained interference pattern. We observe an average intensity
`I=I_(1)+2sqrt(I_(1)I_(2))cosphi`
Now, `cosphi=0` in one complete cycle.
`:.I=I_(1)+I_(2)` which is `4I_(0)`