Question

In a Young's double slit experiment, the fringe width is found to be 0.4 mm. If the whole apparatus is immersed in water of refractive index `(4/3)`, without disturbing the geometrical arrangement, the new fringe width will be :

Options

• 0.30 mm

• 0.40 mm

• 0.53 mm

• 450 microns

Answer 1

0.30 mm

Explanation:

While in air, fringe width

β = `(lambda"D")/"d"` = 0.4 mm

When immersed in liquid, fringe width

β' = `(lambda"'""D")/"d"=lambda/mu"D"/"d"=1/mu((lambda"D")/"d")`

= `1/((4/3))(0.4)`

= 3 (0.1)

= 0.3 mm