A double-slit is illuminated by sodium light $(\lambda =5893 \text{Å})$. In the double-slit the distance between the two slits is $0.050 \mathrm{cm}$. The interference pattern is obtained on a screen placed at a distance of $1.00 \mathrm{m}$. Calculate the distance between the fifth bright fringe on one side of the central fringe and the fifth bright fringe on the other side.

In Young’s double-slit experiment, the slits are $0.05 \mathrm{cm}$ apart and the interference fringes are obtained on a screen $1 \mathrm{m}$ away from the slits. The slits are illuminated by sodium light ($5893 \text{Å}$). Find the distance between 4th bright fringe on one side and 3rd bright fringe on the other side of the central bright fringe.

In Young’s double-slit experiment, the separation between the slits is $0.15 \mathrm{mm}$ and the fringes are obtained on a screen distant $0.75 \mathrm{m}$ from the slits. If the third dark fringe is at a distance of $5.5 \mathrm{mm}$ from the central (bright) fringe, find the wavelength of light used. What will be the distance of the same dark fringe from the centre, if the entire apparatus is immersed in water? The refractive index of water is $\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$3$}\right.$.

The fringe-width in Young’s experiment, when the separation between the slits is $0.5 \mathrm{mm}$ and the distance of the screen from the slits in $1.5 \mathrm{m}$, is $1.8 \mathrm{mm}$. Find the path difference between the interfering waves at the position of first-order maximum.