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 . . . . . .

In the figure,the intensity of waves arriving at $D$ from two coherent sources $S_1$ and $S_2$ is $2I_0$ each. The wavelength of the wave is $\lambda = 8\,m$. The resultant intensity at $D$ will be:

For constructive interference to take place between two monochromatic light waves of wavelength $\lambda$, the path difference should be

Two waves having intensity $I$ and $9I$ produce interference. If the resultant intensity at a point is $7I$,what is the phase difference between the two waves?........$^o$

Interference fringes are produced on a screen by using two light sources of intensities $I$ and $9I$. The phase difference between the beams is $\frac{\pi}{2}$ at the point $P$ and $\pi$ at the point $Q$ on the screen. The difference between the resultant intensities at point $P$ and $Q$ is (in $I$)

Interference fringes are produced on the screen by using two light sources of intensities $I$ and $9I$. The phase difference between the beams is $\pi / 2$ at point $P$ and $\pi$ at point $Q$ on the screen. The difference between the resultant intensities at points $P$ and $Q$ is $(\cos 90^{\circ}=0, \cos 180^{\circ}=-1)$. (in $I$)