Interference (Young's experiment) and an adhesive tape

[zimo]

Homework Statement

At a young's experiment arrangement, there is a 500nm light beam, a distance of 1m from the slits to the screen and a 0.25mm between the two slits
In what way the interference pattern will change if an adhesive tape is being taped to one of the slits with a 1mm thickness and an index of 1.5 (diffraction can be left out of the calculation)

Homework Equations

Xmax = nD[Lambda]/d

The Attempt at a Solution

The problem is presented in a general way, I can't find out what is the point of the adhesive tape addition to the problem.
Can anyone please give a clarification and a possible direction?

 

[ideasrule]

Interference depends on the optical path length difference between two paths. Optical path length depends on the index of refraction of the material that the light is passing through, so adding tape increases this path length for one path but not the other. This changes the interference pattern.