In Young’s double slit experiment the separation d between the slits is 2 mm, the wavelength $$\lambda $$ of the light used is 5896 $$\mathop A\limits^0 $$ and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is 0.20^o. To increase the fringe angular width to 0.21^o (with same $$\lambda $$ and D) the separation between the slits needs to be changed to

Unpolarised light is incident from air on a plane surface of a material of refractive index $$\mu $$. At a particular angle of incidence i, it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation?

The ratio of resolving powers of an optical microscope for two wavelength $$\lambda $$₁ = 4000 $$\mathop A\limits^ \circ $$ and $${\lambda _2}$$ = 6000 $$\mathop A\limits^ \circ $$ is

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8^th bright fringe in the medium lies where 5^th dark fringe lies in air. The refractive index of the medium is nearly