In a double-slit interference experiment,if the path difference at a point on the screen for yellow light is $3\lambda/2$,then the fringe at that point will be . . . . . .

An interference pattern is obtained with two coherent sources of intensity ratio $n:1$. The ratio $\frac{I_{\text{Max}}-I_{\text{Min}}}{I_{\text{Max}}+I_{\text{Min}}}$ will be maximum if

Two beams of light having intensities $I$ and $4I$ interfere to produce fringes on a screen. The phase difference between the beams at point $A$ is $\pi/2$ and at point $B$ is $2\pi$. Find the resultant intensities at points $A$ and $B$.

The wave nature of light is verified by

$A$ beam with wavelength $\lambda$ falls on a stack of partially reflecting planes with separation $d$. The angle $\theta$ that the beam should make with the planes so that the beams reflected from successive planes may interfere constructively is (where $n = 1, 2, \dots$)

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