Answer:
The distance between interference fringes increases.
Explanation:
In a double-slit diffraction pattern, the distance of the n-order fringe from the centre of the pattern is
where is the wavelength of the light, D the distance of the screen, and d the separation between the slits.
If we take two adjacent fringes, n and (n+1), their distance is
so, we see that it is inversely proportional to the slit separation, d.
Therefore, if the separation between the slits decreases, the distance between the interference fringes increases.