If the slit width is 2 mm and wavelength of light used is $4000\mathop {\rm{A}}\limits^{\rm{o}}$, then Fresnel distance is nearly

In a Young's double slit experiment, if the distance between two slits is reduced by a factor of 2 and the wavelength of light is increased 4 times then the distance between two maxima will become $\_\_\_\_$ times the original value

In an interference pattern of Young's double slit experiment, at a point we observe the 12 th order maximum for a monochromatic light source with wavelength $6000 \mathop {\rm{A}}\limits^{\rm{o}} $. What order will be visible here, if the source is replaced by a light of wavelength $4800 \mathop {\rm{A}}\limits^{\rm{o}} $ ?