In a Young's double slits experiment, the ratio of amplitude of light coming from slits is $$2: 1$$. The ratio of the maximum to minimum intensity in the interference pattern is:

The ratio of intensities at two points $$\mathrm{P}$$ and $$\mathrm{Q}$$ on the screen in a Young's double slit experiment where phase difference between two waves of same amplitude are $$\pi / 3$$ and $$\pi / 2$$, respectively are

The width of fringe is $$2 \mathrm{~mm}$$ on the screen in a double slits experiment for the light of wavelength of $$400 \mathrm{~nm}$$. The width of the fringe for the light of wavelength 600 $$\mathrm{nm}$$ will be: