Two coherent sources of intensities $I$ and $4I$ interfere. The maximum and minimum intensities of the resultant wave are:

For a distinct interference pattern,the condition is that the ratio of intensities of light produced by both sources must be .....

The path difference between two interference waves at a point on a screen is $11.5 \lambda$. The point is

$A$ and $B$ are two interfering sources where $A$ is ahead in phase by $54^{\circ}$ relative to $B$. The observation is taken from point $P$ such that $PB-PA=2.5 \lambda$. Then the phase difference between the waves from $A$ and $B$ reaching point $P$ is (in rad) (in $\pi$)

Two coherent sources are kept at a distance of $d = 2 \lambda$. $A$ large screen is placed perpendicular to the line joining the sources. Determine the total number of maximas observed on the screen. (Here,$\lambda$ is the wavelength of light.)

Interference fringes are produced on a screen by using two light sources of intensities $I$ and $9I$. The phase difference between the beams is $\frac{\pi}{2}$ at the point $P$ and $\pi$ at the point $Q$ on the screen. The difference between the resultant intensities at point $P$ and $Q$ is (in $I$)