In the Young’s double slit experiment, the ratio of intensities of bright and dark fringes is 9. This means that :-
(A) The intensities of individual sources are 5 and 4 units respectively
(B) The intensities of individual sources are 4 and 1 units respectively
(C) The ratio of their amplitudes is 3
(D) The ratio of their amplitudes is 2

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 :

In a Young’s double slit experiment the intensity at a point where the path difference is λ/6 (λ being the wavelength of the light used) is I. If I0 denotes the maximum intensity, I/I0 is equal to :

In the Young’s double slit experiment, for which colour the fringe width is least :