For a distinct interference pattern to be observed,the necessary condition is that the ratio of the intensity of light emission by both sources should be

The intensity of light depends upon:

Two beams of light having intensities $I$ and $4I$ interfere to produce fringes on a screen. The phase difference between the beams at point $A$ is $\pi/2$ and at point $B$ is $2\pi$. Find the resultant intensities at points $A$ and $B$.

Two coherent sources whose intensity ratio is $64: 1$ produce interference fringes. The ratio of intensities of maxima and minima is

Two coherent sources separated by a distance $d$ are radiating in phase with a wavelength $\lambda$. $A$ detector moves in a large circle around the two sources in the plane of the two sources. The angular position of the $n = 4$ interference maxima is given as

Two monochromatic beams of intensities $I$ and $4I$ respectively are superposed to form a steady interference pattern. The maximum and minimum intensities in the pattern are