Q.
As shown in the figure, in Young's double slit experiment, a thin plate of thickness $t=10\, \mu m$ and refractive index $\mu=1.2$ is inserted infront of slit $S_1$. The experiment is conducted in air $(\mu-1)$ and uses a monochromatic light of wavelength $\lambda=500\, nm$. Due to the insertion of the plate, central maxima is shifted by a distance of $x \beta_0 . \beta_0$ is the fringe-width befor the insertion of the plate. The value of the $x$ is ___
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