Two identical light waves, propagating in the same direction, have a phase difference $\delta$. After they superpose, the intensity of the resulting wave will be proportional to

The intensities of two coherent sources are $9I$ and $4I$. The intensity at a point where the path difference is $11\lambda$ is:

When a light wave enters from air into water, which quantity does not change?

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 $x = 5 \lambda$.

$A$ ray of light from a monochromatic point source of light is incident at a point on the screen. If a thin mica film of thickness $t$ and refractive index $n$ is introduced in its path,then the optical path

Two light waves of intensities $I_1$ and $I_2$ having the same frequency pass through the same medium at a time in the same direction and interfere. The sum of the minimum and maximum intensities is