The path difference between two identical light waves at a point $$Q$$ on the screen is $$3 \mu \mathrm{m}$$. If wavelength of the waves is $$5000 \mathop A\limits^o$$, then at point $$Q$$ there is

Of the two slits producing interference in Young's experiment, one is covered with glass so that light intensity passing is reduced to $$50 \%$$. Which of the following is correct?

In a biprism experiment, monochromatic light of wavelength '$$\lambda$$' is used. The distance between two coherent sources '$$\mathrm{d}$$' is kept constant. If the distance between slit and eyepiece '$$\mathrm{D}$$' is varied as $$D_1, D_2, D_3 \& D_4$$ and corresponding measured fringe widths are $$Z_1, Z_2, Z_3$$ and $$Z_4$$ then

$$\mathrm{A}$$ and $$\mathrm{B}$$ are two interfering sources where $$\mathrm{A}$$ is ahead in phase by $$54^{\circ}$$ relative to B. The observation is taken from point $$\mathrm{P}$$ such that PB $$-$$ PA = 2.5 $$\lambda$$. Then the phase difference between the waves from A and B reaching point P is (in rad)