The phenomenon of interference is shown by

Two monochromatic coherent light waves of amplitudes $A$ and $2A$,interfering at a point,have a phase difference of $60^{\circ}$. The intensity at that point will be proportional to (in $A^2$)

Four monochromatic and coherent sources of light,emitting waves in phase of wavelength $\lambda$,are placed at the points $x = 0, d, 2d$,and $3d$ on the $x$-axis. The intensity of the waves reaching a point $P$ far away on the $+x$ axis from each of the four sources is almost the same,and equal to $I_0$. Then,

For a distinct interference pattern to be observed,the necessary condition is that the ratio of the intensity of light emission by both sources should be

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

If the ratio of the amplitudes of two interfering sources is $3 : 5$,then the ratio of the intensity of maxima and minima in the interference pattern will be