Two coherent monochromatic light beams of intensities $I$ and $4I$ are superimposed. The difference between maximum and minimum possible intensities in the resulting beam is $x I$. The value of $x$ is . . . .

The following figure shows sources $S_1$ and $S_2$ that emit light of wavelength $\lambda$ in all directions. The sources are exactly in phase and are separated by a distance equal to $1.5\lambda$. If we start at the indicated start point and travel along path $1$ and $2$,the interference produces a maxima all along:

Light waves from two coherent sources arrive at two points on a screen with path difference of $0$ and $\frac{\lambda}{2}$. The ratio of intensities at the points is $(\cos 0^{\circ}=1, \cos \pi=-1)$.

For the sustained interference of light,the necessary condition is that the two sources should

$S_{1}$ and $S_{2}$ are coherent point sources of light located in the $xy$-plane at points $(0,0)$ and $(0,3\lambda)$ respectively. Here $\lambda$ is the wavelength of light. At which one of the following points (given as coordinates) will the intensity of interference be maximum?

Two light waves of intensities $I_1$ and $I_2$ having the same frequency pass through the same medium at a time in the same direction and interfere. The sum of the minimum and maximum intensities is