In Young's double-slit experiment,the width of one slit is twice that of the other. What is the ratio of the maximum to the minimum intensity?

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 ...... $mm$.

In Young's double slit experiment shown in the figure,$S_1$ and $S_2$ are coherent sources and $S$ is the screen having a hole at a point $1.0 \, mm$ away from the central line. White light ($400 \, nm$ to $700 \, nm$) is sent through the slits. Which wavelength passing through the hole has strong intensity (in $, nm$)? (Given: $d = 0.5 \, mm$,$D = 50 \, cm$)

In the Young's double slit experiment,the ratio of intensities of bright and dark fringes is $9$. This means that

In Young's double-slit experiment,when two light waves form the third minimum,they have:

Two coherent sources of light are placed at points $(-\frac{5a}{2}, 0)$ and $(+\frac{5a}{2}, 0)$. The wavelength of the light is $\lambda = \frac{4a}{3}$. How many maxima will be obtained on a planar circle of large radius with its center at the origin?