The two coherent sources of equal intensity produce a maximum intensity of $100$ units at a point. If the intensity of one of the sources is reduced by $36\%$ by reducing its width,then the intensity of light at the same point will be:

Two point sources $S_1$ and $S_2$ separated by a distance $10 \mu m$ emit light waves of wavelength $4 \mu m$ in phase. $A$ circular wire of radius $40 \mu m$ is placed around the sources as shown in the figure,where $O$ is the centre of the circle and $OS_1 = OS_2$. Determine the nature of the interference at points $A, B, C,$ and $D$.

In an interference experiment,the path difference between two interfering waves at a point $A$ on the screen is $\lambda/3$,where $\lambda$ is the wavelength of these waves,and at another point $B$ the path difference is $\lambda/6$. The ratio of intensities at points $A$ and $B$ is . . . . . . .

An interference pattern is observed at $P$ due to the superimposition of two rays coming from a source $S$ as shown in the figure. The value of $l$ for which maxima is obtained at $P$ is: ($R$ is a perfectly reflecting surface)

Two waves having same intensity $I_{0}$ and originated from two non-coherent sources superpose at a point. The average intensity at that point is . . . . . . .

Light waves producing interference have their amplitudes in the ratio $3: 2$. The intensity ratio of maximum and minimum of interference fringes is