Most Important Selected Qs for JEE AdvancedPhysicsWave Optics
Consider the situation shown in the figure. Two slits S₁ and S₂ are placed symmetrically about the line OP which is perpendicular to screen. The space between screen and slits is filled with a liquid of refractive index ₃ . A plate of thickness t and refractive index ₂ is placed in front of one of the slit. A source S is placed above OP at a distance d . Choose the correct alternatives. [ ( . . Given that . D =1 ~m ,
Options
- APosition of central maxima from point P is 2 mm
- BPosition of central maxima from point P is 2 9 ~mm
- CThickness of glass slab so that central maxima forms at point P is 20 3 10⁻⁶ ~m
- DIf glass slab is removed, the central maxima shifts by a distance of 2 mm
Correct answer
C. Thickness of glass slab so that central maxima forms at point P is 20 3 10⁻⁶ ~m
Step-by-step solution
(i) Path difference in air is x= d^2 D + ( ₂- ₃ ) t+ ₃ y d 2 D for position of central maxima x =0 y= 2 9 ~mm (ii) Thickness of the slab so that central maxima forms at point P t ( ₂- ₃ )+ d^2 D =0 t= (2 10⁻³ )^2 0.6 = 20 3 10⁻⁶ ~m