In a Young'sdouble slit experiment the fringes are displaced by a distance x when a glass plate of refractive index 1.5 is introduced in the path of one of the bemas.When this plate is replaced by another plate of the same thickness, the shift of fringes is (3)/(2) x.The refractive index of the second plate is :

In a Young'sdouble slit experiment the fringes are displaced by a dist

1.	In a Young'sdouble slit experiment the fringes are displaced by a distance x when a glass plate of refractive index 1.5 is introduced in the path of one of the bemas.When this plate is replaced by another plate of the same thickness, the shift of fringes is (3)/(2) x.The refractive index of the second plate is :
Answer» 2.25 `2.0` `1.75` `1.25` SOLUTION :Path difference with glass plate = `(mu - 1) t` shift of FRINGE due to path difference `lambda` is `beta = (D)/(d) lambda` Fringe shift in FIRST case is `X = (beta)/(lambda)(mu - 1) t` ...(i) Fringe shift in second case is `3/2x = (beta)/(lambda)(mu. - 1)t` `therefore (x)/(3/2x) = ((beta/lambda)(mu - 1) t)/(beta/lambda)(mu. -1)t = (mu - 1)/(mu. - 1)` then `mu . = 1.75` `because mu = 15`

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