In a YDSE experiment, the upper slit is covered by a thin glass plate of refractive index µ1 = 2.1 while the lower slit is covered by another glass plate having the same thickness as the first one but having refractive index µ2 = 2.4 . Interference pattern is observed using light of wavelength λ = 600 nm . It is found that the point P on the screen where the central maxima fell before the glass plates were inserted, now has 3/4 the original intensity. It is further observed that what used to be the fourth maxima earlier, lies below the point P while the fifth minima lies above the point P. Neglect absorption of light by glass plates. If thickness of the glass plates is ‘t’ in meter, find value of (3t x 106)/5 ?
