Answer:
y = 3.36 mm
Step-by-step explanation:
The wavelength of the light,

Separation between the two slits, d = 0.25 mm

The separation between the light image and the screen, L = 1.4 m
m = 1
the distance of the bright fringes from the central maximum,


y = 0.00336 m
y = 3.36 mm