Two beams of light having intensities $I$ and $4I$ interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\frac{\pi}{2}$ at point $A$ and $\pi$ at point $B$. Then the difference between the resultant intensities at $A$ and $B$ is (in $I$)

Two waves have their amplitudes in the ratio $1 : 9$. The maximum and minimum intensities when they interfere are in the ratio

The intensity ratio of two coherent sources of light is $p$. They are interfering in some region and produce an interference pattern. Then the fringe visibility is

Explain the pattern of diffraction produced by two slits by drawing a figure.

Obtain the conditions for constructive interference and destructive interference.

In Young's double slit experiment,monochromatic light of wavelength $5000 \ \mathring{A}$ is used. The slits are $1.0 \ mm$ apart and the screen is placed at $1.0 \ m$ away from the slits. The distance from the centre of the screen where intensity becomes half of the maximum intensity for the first time is . . . . . . $\times 10^{-6} \ m$.