Two light waves of intensities $I$ and $2I$ superimpose on each other. If the path difference between the light waves reaching a point is $12.5 \%$ of the wavelength of the light,then the resultant intensity at the point is (Both the light waves have same wavelength).

Two coherent plane waves of identical frequency, polarization, and intensity $I$ interfere at a point where they differ in phase by $60^{\circ}$. What is the resulting intensity?

Two coherent light sources $A$ and $B$ are at a distance $3\lambda$ from each other (where $\lambda$ is the wavelength). Find the distances from $A$ on the $x$-axis at which constructive interference occurs.

Two coherent sources $S_1$ and $S_2$ and a screen are arranged as shown in the figure. If the distance between the two coherent sources is $n \lambda$ and the distance of the screen from the nearer coherent source $S_2$ is $D$,then the distance of the first bright fringe on the screen from the point $O$ is (where $\lambda$ is the wavelength of the light emitted by the coherent sources).

Two plane polarized light waves combine at a certain point whose electric field components are $E_1 = E_0 \sin(\omega t)$ and $E_2 = E_0 \sin(\omega t + \frac{\pi}{3})$. Find the amplitude of the resultant wave.

Two coherent monochromatic light beams of intensities $4 I$ and $9I$ are superimposed. The difference between the maximum and minimum intensities in the resulting interference pattern is $xI$. The value of $x$ is . . . . . . .