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

$A$ laser is a coherent source because it contains

Two coherent sources of intensity ratio $9:4$ produce interference. The intensity ratio of maxima and minima of the interference pattern 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:

Light waves are emitted by a common source. For what time interval will the phase remain constant?

If two sources of light emit waves of different amplitudes and interfere, then: