In a Young's double-slit experiment,the wavelength of light used is $6000 \, \mathring A$. The phase difference between the central bright fringe and the third bright fringe is .......

In a Young's double-slit experiment,the slits are $2 \, mm$ apart and are illuminated by a mixture of two wavelengths $\lambda_1 = 7500 \, \mathring{A}$ and $\lambda_2 = 9000 \, \mathring{A}$. At what distance from the central maximum on a screen $2 \, m$ away will a bright fringe from one interference pattern coincide with a bright fringe from the other?

The fringe width in an interference pattern is $X$. The distance between the sixth dark fringe from one side of the central bright band to the fourth bright fringe on the other side is: (in $X$)

The distance between two coherent sources is $1 \ mm$. The screen is placed at a distance of $1 \ m$ from the sources. If the distance of the third bright fringe is $1.2 \ mm$ from the central fringe, the wavelength of light used is:

State two conditions for obtaining sustained interference of light. In Young's double-slit experiment,using light of wavelength $400 \, nm$,interference fringes of width $'X'$ are obtained. If the wavelength of light is increased to $600 \, nm$ and the separation between the slits is halved,find the ratio of the distances between the screen and the slits in the two arrangements if the fringe width remains the same.

An interference pattern was made by using red light. If the red light is replaced with blue light,the fringes will become