Two waves coming from two coherent sources,having different intensities,interfere. The ratio of their maximum intensity to the minimum intensity is $25$. What is the ratio of the intensities of the sources?

$n$ 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:

$S_{1}$ and $S_{2}$ are coherent point sources of light located in the $xy$-plane at points $(0,0)$ and $(0,3\lambda)$ respectively. Here $\lambda$ is the wavelength of light. At which one of the following points (given as coordinates) will the intensity of interference be maximum?

If the wavelength of light is $4000 \text{ Å}$, then the number of waves in $1 \text{ mm}$ length will be . . . . . . -

Two coherent sources of light interfere. The intensity ratio of two sources is $1:4$. For this interference pattern,if the value of $\frac{I_{\max} + I_{\min}}{I_{\max} - I_{\min}}$ is equal to $\frac{2\alpha + 1}{\beta + 3}$,then the value of $\frac{\alpha}{\beta}$ will be:

Explain the intensity at the point of superposition of waves emanating from coherent and incoherent sources.