Question
How does the fringe width of interference fringes change, when the whole apparatus of Young's experiment is kept in a liquid of refractive index 1.13?
Solution
Fringe width is directly proportional to wavelength and inversely proportional to refractive index.
The formula is given by,
In air, Fringe width, x =
In medium,
where,
d is the distance between the slits and,
D is the distance between the screen and the slit.
Therefore, fringe width decreases by a factor of when placed in the liquid.