The width of the fringes obtained in the Young's double slit experiment is $$2.6 \mathrm{~mm}$$ when light of wave length $$6000^{\circ} \mathrm{A}$$ is used. If the whole apparatus is immersed in a liquid of refractive index 1.3 the new fringe width will be :

In a single slit diffraction experiment, for slit width '$$\alpha$$' the width of the central maxima is '$$\beta$$'. If we double the slit width then the corresponding width of the central maxima will be:

In Young's double slit interference experiment, using two coherent waves of different amplitudes, the intensities ratio between bright and dark fringes is 3 . Then, the value of the ratio of the amplitudes of the wave that arrive there is

In Young's double slit experiment, the ratio of maximum and minimum intensities in the fringe system is $$9: 1$$. The ratio of amplitudes of coherent sources is