In a Young's double slit experiment, the slit separation d is 0.3 m m and the screen distance D is 1 m . A parallel beam of light of wavelength 600 n m is incident on the slits at angle α as shown in figure. On the screen, the point O is equidistant from the slits and distance P O is 11.0 m m . Which of the following statement(s) is/are correct?

Step-by-step solution

Path difference at “ P ” , ∆ x = d sin ⁡ α + d sin ⁡ θ θ , α : s m a l l a n g l e , sin ⁡ θ ≅ tan ⁡ θ = y D and sin ⁡ α ≈ α ⇒ ∆ x = d α + d y D A ∆ x = 3 m m × 0.36 π × π 180 + 0 = 600 n m 600 n m = n λ n = 1 Constructive interference ⇒ A is incorrect B Fringe width does not depend on α . ⇒ B is incorrect C ∆ x = 0.3 m m × 0.36 π × π 180 + 0.3 m m × 11 m m 1000 = 39 × 10 - 4 m m Now, ∆ x = 39 × 10 - 4 = 2 n - 1 × 600 × 10 - 9 × 10 3 2 ⇒ n = 7 Destructive interference happened ⇒ correct D α = 0 ∴ ∆ x = d y / D = 0.