Wave Optics

A double slit experiment is immersed in water of refractive index 1.33. The slit separationis 1 \(\mathrm{mm}\) and the distance between slit and screen is \(1.33 \mathrm{~m}\). The slits are illuminated by a light of wavelength \(6300\,\mathop A\limits^o\). The fringewidth is