In Young's double-slit experiment,which of the following statements is correct?

In a Young's double-slit experiment,the slits are $2 \, mm$ apart and are illuminated by a mixture of two wavelengths $\lambda_1 = 7500 \, \mathring{A}$ and $\lambda_2 = 9000 \, \mathring{A}$. At what distance from the central maximum on a screen $2 \, m$ away will a bright fringe from one interference pattern coincide with a bright fringe from the other?

In Young's double slit experiment,the amplitudes of two sources are $3a$ and $a$ respectively. The ratio of intensities of bright and dark fringes will be (in $:1$)

In Young's double slit experiment,the distance between two sources is $0.1 \, mm$. The distance of the screen from the sources is $20 \, cm$. The wavelength of light used is $5460 \, \mathring{A}$. The angular position of the first dark fringe is: (in $^\circ$)

In two different Young's double-slit experiments,the fringe width is the same when the ratio of wavelengths is $1:2$. If the ratio of the distance between the slits in the two cases is $2:1$,then the ratio of the distance between the slits and the screen in the two experiments is:

Two slits at a distance of $1\, mm$ are illuminated by light of wavelength $6.5 \times 10^{-7}\, m$. The interference fringes are observed on a screen placed at a distance of $1\, m$. The distance between the third dark fringe and the fifth bright fringe will be......$mm$.