If the source of light used in a Young’s double slit experiment is changed from red to violet. 

Fringe width,
$\beta =\frac{\lambda .D}{d}$
Here,  wavelength of light
D = Distance of screen from source
d = Distance between the sits
$\because {\lambda }_R>{\lambda }_V$
As wavelength of light decreases, fringe width will decrease and fringe line will come closer.