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:

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

Two identical coherent sources are placed on a diameter of a circle of radius $R$ at a separation $x (x << R)$,symmetrically about the center of the circle. The sources emit waves of identical wavelength $\lambda$. Find the number of points on the circle with maximum intensity,given $x = 5 \lambda$.

Two monochromatic light waves of amplitudes $3 A$ and $2 A$ interfering at a point have a phase difference of $60^{\circ}$. The intensity at that point will be proportional to (in $A^{2}$)

Two light waves of intensity $I$ and $4I$ superpose at point $A$ with zero phase difference and at point $B$ with a phase difference of $\frac{\pi}{2}$. Calculate the difference of resultant intensities at point $A$ and $B$. (in $I$)

$S_{1}$ 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?