Two light beams of intensities $I$ and $4I$ produce an interference pattern on a screen. If the phase difference between them at point $A$ is $\pi/2$ and at point $B$ is $2\pi$,find the difference between the resultant intensities at points $A$ and $B$.

Two coherent sources of intensities,$I_1$ and $I_2$ produce an interference pattern. The maximum intensity in the interference pattern will be

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

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 $OS_1 = OS_2$. Then:

What are coherent sources and incoherent sources?

Two waves coming from two coherent sources,having different intensities,interfere. The ratio of their maximum intensity to the minimum intensity is $25$. What is the ratio of the intensities of the sources?