In a Young's double slit experiment wavelength of light used is $6000 \mathop {\rm{A}}\limits^{\rm{o}}$. The first order maxima and tenth order maxima fall at 14.50 mm and 16.75 mm from the particular reference point in the interference pattern respectively. If the wavelength is changed to $5500 \mathop {\rm{A}}\limits^{\rm{o}}$ then the position of zero order and tenth order maxima are respectively

[The other arrangements remaining same]

In a pure silicon crystal electron-hole concentration is $10^{16}$ per $\mathrm{m}^3$ at 301 K . Now $10^{21}$ atoms of phosphorus are added per cubic metre. The new hole concentration in silicon is (in per $\mathrm{m}^3$ )

Assuming human pupil to have radius of 0.25 cm and comfortable viewing distance of 25 cm , the minimum separation between the two objects that human eye can resolve at 500 nm wavelength is nearly