A Young's double slit apparatus has slits separated by 0.25mm and a screen 48cm away from the slits. The whole apparatus is immersed in water and the slits are illuminated by the red light (`lambda=700nm` in vacuum.) Find the fringe width of the pattern formed on the screen. `(mu_w = 4//3)`

Explanation

Wavelength in water, `lambda' = lambda/mu`
Fringe width, `omega = (lambda'D)/(d) = (lambdaD)/(mud)`
` = ((700 xx 10^(-9))(0.48))/((4//3)(0.25 xx 10^(-3)))`
` = 10^(-3)`
= 1mm.