What is the effect on the interference pattern observed in a young's double slit experiment in the following cases when:
(i) screen is moved away from the plane of the slits.
(ii) seperation between the slits is increased.
(iii) width of the slits are doubled.
Give reasons for your ans....
The fringe width is given by
w = λD/d
(1) In this case, as we increase 'D' the fringe width will increase as well (from the relation) and its intensity decrease.
(2) As 'd' increases fringe width decreases and intensity increases.
(3) The fringe width would be halved by using the above formula.