$n$ identical waves each of intensity $I_0$ interfere with each other. The ratio of maximum intensities if the interference is $(i)$ coherent and $(ii)$ incoherent is:

The wavelength of light visible to the human eye is of the order of:

Two light rays having the same wavelength $\lambda$ in vacuum are in phase initially. Then the first ray travels a path $L_1$ through a medium of refractive index $\mu_1$,while the second ray travels a path of length $L_2$ through a medium of refractive index $\mu_2$. The two waves are then combined to observe interference. The phase difference between the two waves is

Two waves having intensity $I$ and $9I$ produce interference. If the resultant intensity at a point is $7I$,what is the phase difference between the two waves?........$^o$

Considering interference between two sources of intensities $I$ and $4I$,the intensity at a point where the phase difference is $\pi$ is $(\cos \pi = -1)$.

Define constructive interference. $OR$ Define destructive interference.