Interference was observed in an interference chamber when air was present. Now,the chamber is evacuated and if the same light is used,a careful observer will see:

On using red light $(\lambda = 6600 \ \text{Å})$ in Young's double slit experiment, $60$ fringes are observed in the field of view. If violet light $(\lambda = 4400 \ \text{Å})$ is used, the number of fringes observed will be

In Young's double-slit experiment,if the distance between the slits is reduced to half and the distance between the slit and the screen is doubled,then the fringe width

In a Young's double-slit experiment,two slits are separated by a distance of $3 \, mm$ and are illuminated by light of wavelength $480 \, nm$. The screen is at a distance of $2 \, m$ from the plane of the slits. Find the separation between the $8^{th}$ bright fringe and the $3^{rd}$ dark fringe with respect to the central fringe.

$A$ beam of light consisting of wavelengths $650 \ nm$ and $550 \ nm$ illuminates the Young's double slits with separation of $2 \ mm$ such that the interference fringes are formed on a screen, placed at a distance of $1.2 \ m$ from the slits. The least distance of a point from the central maximum, where the bright fringes due to both the wavelengths coincide, is . . . . . . $\times 10^{-5} \ m$.

Two slits separated by $0.5 \,mm$ are illuminated by light of wavelength $500 \,nm$. The screen is at a distance of $120 \,cm$ from the slits. The phase difference between the interfering waves at a point $3 \,mm$ on the screen from the central bright fringe is ........... .