Q.

In a Young's double slit experiment, the intensity at a point is (14)th of the maximum intensity, the minimum distance of the point from the central maximum is __________ μm. (Given λ=600 nm, d=1.0 mm, D=1.0 m)


Ans.

(200)

Intensity at a point is given by

I=I0cos2(Δϕ2)

⇒According to question I04=cos2(Δϕ2)

Δϕ=2π3

∴ Δϕ=2πλ(ydD)=2π3

⇒y=λD3d=600×10-9×13×10-3=2×10-4 m