In Young's double-slit experiment, the fringe width will increase if ......

In a Young's double-slit experiment,the slits are separated by $0.28 \; mm$ and the screen is placed $1.4 \; m$ away. The distance between the central bright fringe and the fourth bright fringe is measured to be $1.2 \; cm$. Determine the wavelength of light used in the experiment (in $nm$).

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

The distance between two coherent sources is $0.1 \, mm$. The fringe-width on a screen $1.2 \, m$ away from the source is $6.0 \, mm$. The wavelength of light used is ......... $\mathring{A}$.

$A$ light of wavelength $500 \, nm$ is incident on a Young's double-slit. The distance between the slits and the screen is $D = 1.8 \, m$ and the distance between the slits is $d = 0.4 \, mm$. If the screen moves with a speed of $4 \, m/s$,with what speed will the first maxima move? (in $mm/s$)

In a Young's double-slit experiment,light of two wavelengths $6500 \, \mathring A$ and $5200 \, \mathring A$ is used. Find the distance of the third bright fringe from the central maximum for the wavelength $6500 \, \mathring A$. The distance between the two slits is $2 \, mm$ and the distance between the plane of the slits and the screen is $120 \, cm$.