Figure shows two coherent sources `S_(1)` and `S_(2)` vibrating in same phase. AB in an irregular wire lying at a far distance from the sources `S_(1)` and `S_(2). `Let `(lambda)/(d) = 10^(-3) /_ BOA = 0.12^(@)`. How many bright spots will be seen on the wire, including points A and B?

Answer

3

Explanation

Angular width `=(lamda)/d=10^(-3)` (given)
`:.` No. of fringes within `0.12^(@)` will be
`n=(0.12xx2pi)/(360xx10^(-3))~=[2.09]`
`:.` The number of bright spots will be three.
Hence (B).