Two light waves with amplitudes in the ratio $3 : 1$ produce interference. The ratio of the maximum to minimum intensity is

Two light waves having the same wavelength $\lambda$ in vacuum are in phase initially. Then the first wave travels a path $L_{1}$ through a medium of refractive index $n_{1}$ while the second wave travels a path of length $L_{2}$ through a medium of refractive index $n_{2}$. After this the phase difference between the two waves is:

Two waves having intensities in the ratio $25 : 4$ produce interference. The ratio of the maximum to the minimum intensity is

The frequency of a light wave with a wavelength of $500 \, \mathring A$ is $....... \, Hz$.

The optical path difference between two identical light waves arriving at a point is $31.5 \lambda$,where $\lambda$ is the wavelength of light used. The point is [Given: Two light sources are coherent]

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