The ratio of maximum to minimum intensity in an interference pattern is $25 : 16$. Calculate the ratio of maximum to minimum amplitude.

Two identical light waves having phase difference $\phi$ propagate in the same direction. When they superpose,the intensity of the resultant wave is proportional to

The light beams of intensities in the ratio of $9: 1$ are allowed to interfere. What will be the ratio of the intensities of maxima and minima?

The two interfering waves have intensities in the ratio $9 : 4$. The ratio of intensities of maxima and minima in the interference pattern will be

What is the path difference for destructive interference?

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,