Q.

In a Young’s double slit experiment, the intensity at a point is (14)thof the maximum intensity. The minimum distance of the point from the central maximum is _____ µm. 

(Given: λ=600nm, d=1.0mm, D=1.0m)                     [2024]


Ans.

(200)       I=I0cos2(Δϕ2)

                 14=cos2(Δϕ2)

                 Δϕ=2πλΔxΔϕ=2π3=2πλΔxΔx=λ3

                 Δx=dyD=λ3

                 y=λD3d=600×10-9×13×10-3=2×10-4m=200μm