Wave Optics PYQs

In Young’s double slit experiment, using monochromatic light of wavelength λ, the intensity of light at a point on the screen where the path difference is λ is K units. The intensity of light at a point where the path difference is λ/3 will be:

Two slits in Young's experiment have widths in the ratio $1:25$. The ratio of intensity at the maxima and minima in the interference pattern, $\dfrac{I_{\max}}{I_{\min}}$, is:

In Young's double slit experiment, the slits are $2\,\text{mm}$ apart and are illuminated by photons of wavelengths $\lambda_1=12000\,\text{Å}$ and $\lambda_2=10000\,\text{Å}$. At what minimum distance from the common central bright fringe on a screen $2\,\text{m}$ from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other?