The central fringe of an interference pattern produced by light of wavelength $6000 \, \mathring{A}$ is found to shift to the position of the fourth bright fringe after a glass plate of refractive index $1.5$ is introduced in front of one slit. The thickness of the glass plate would be ...... $\mu m$.

In a Young's double-slit experiment,light of wavelength $4800 \, \mathring A$ is used. If both slits are covered by transparent plates of the same thickness $t$ having refractive indices $\mu_1 = 1.5$ and $\mu_2 = 1.8$,and the central bright fringe shifts to the position of the fifth bright fringe,then the thickness of the plates is ....... $\mu m$.

In the figure shown,if a parallel beam of light is incident on the plane of the slits at an angle such that the path difference at point $O$ is $\Delta x = d \sin \theta = d \cdot (\frac{2d/3}{d}) = \frac{2d}{3}$,and if point $O$ is a maxima for monochromatic light,then which of the following cannot be the wavelength of the incident light? [Assume $d << D, \lambda << d$]

$A$ parallel beam of light of wavelength $500 \ nm$ is incident at an angle $30^o$ with the normal to the slit plane in a Young's double-slit experiment. The intensity due to each slit is $I_o$. Point $O$ is equidistant from $S_1$ and $S_2$. The distance between the slits is $1 \ mm$.

As shown in the figure,two point coherent sources $S_1$ and $S_2$ are placed at a small distance $d$ apart. The fringes formed on the screen will be .......

Young's double slit experiment is performed with monochromatic light. $A$ thin film is introduced in front of one of the slits.