In an interference experiment,the spacing between successive maxima or minima is (where the symbols have their usual meanings):

In Young's double slit experiment,white light is used. The separation between the slits is $b$. The screen is at a distance $d$ $(d >> b)$ from the slits. Some wavelengths are missing exactly in front of one slit. These wavelengths are

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 Young's double slit experiment,the phase difference between the light waves reaching the third bright fringe from the central fringe is: $(\lambda = 6000 \ \mathring{A})$

Given below are two statements:
Statement $I$: In a Young's double slit experiment, the angular separation of fringes will increase as the screen is moved away from the plane of the slits.
Statement $II$: In a Young's double slit experiment, the angular separation of fringes will increase when a monochromatic source is replaced by another monochromatic source of higher wavelength.
In the light of the above statements, choose the correct answer from the options given below:

In a $YDSE$ apparatus,two identical slits are separated by $1\, mm$ and the distance between the slits and the screen is $1\, m$. The wavelength of light used is $6000\, \mathring{A}$. The minimum distance between two points on the screen having $75\%$ intensity of the maximum intensity is ......$mm$.