The ratio of intensities at two points $P$ and $Q$ on the screen in a Young's double-slit experiment,where the phase differences between two waves of the same amplitude are $\pi / 3$ and $\pi / 2$ respectively,is:

In $YDSE$ with two identical slits,when the upper slit is covered with a transparent sheet of mica,the second-order minima is observed above the center of the screen and the second-order maxima below it. Which of the following cannot be a possible value of the phase difference caused by the mica sheet?

Two coherent sources $P$ and $Q$ produce interference at point $A$ on the screen,where a dark band is formed between the $4^{\text{th}}$ and $5^{\text{th}}$ bright band. The wavelength of light used is $6000 \text{ Å}$. The path difference between $PA$ and $QA$ is:

In a $YDSE$,the central bright fringe can be identified:

In Young's double slit experiment,the wavelength of light was changed from $7000 \ \mathring{A}$ to $3500 \ \mathring{A}$. While doubling the separation between the slits,which of the following is not true for this experiment?

If the path difference of the point on the screen from two coherent sources is constant, what is the shape of the trajectory of the point on the screen?