Considering interference between two sources of intensities $I$ and $4I$,the intensity at a point where the phase difference is $\pi$ is $(\cos \pi = -1)$.

Two monochromatic light beams of intensity $16$ and $9$ units are interfering. The ratio of intensities of bright and dark parts of the resultant pattern is

Two waves of intensity $I$ undergo interference. The maximum intensity obtained is

In an interference pattern,two waves of intensities $I$ and $4I$ are used. At point $A$,the phase difference is $\frac{\pi}{2}$,and at point $B$,the phase difference is $\pi$. The difference in intensities at points $A$ and $B$ is: (in $I$)

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

$A$ beam with wavelength $\lambda$ falls on a stack of partially reflecting planes with separation $d$. The angle $\theta$ that the beam should make with the planes so that the beams reflected from successive planes may interfere constructively is (where $n = 1, 2, \dots$)