1) In Young's double slit experiment intensity at a point is (1/4) of the maximum intensity. Angular position of this point is (separation between slits is d) A) sin−1(λd) B) sin−1(λ2d) C) sin−1(λ3d) D) sin−1(λ4d) Answer: Option CExplanation:If a is the amplitude of the wave then Imax4 = a2 = a2 +a2 +2aa cosΦ or cos Φ = - 1/2 or Φ = 2π/3 Corresponding path difference, Δx = ϕ×λ2π = (2π/3)×λ2π= λ/3 So, dsinθ=λ3 or θ = sin−1(λ3d)