If the ratio of maximum and minimum intensities is $36 : 1$ in an interference pattern,then the ratio of amplitudes of the interfering waves is

If the wavelength of light is $4000 \, Å$, then the number of waves in a length of $1 \, mm$ will be:

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

Two point sources separated by $d = 5\, \mu m$ emit light of wavelength $\lambda = 2\, \mu m$ in phase. $A$ circular wire of radius $R = 20\, \mu m$ is placed around the sources as shown in the figure. Determine the nature of interference at points $A, B, C,$ and $D$.

Two coherent sources have different intensities. They produce an interference pattern. If the ratio of maximum to minimum intensities is $25:1$,find the ratio of the intensities of the sources.

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