For a second diffraction using X-ray Bragg's equation, for a crystal with separation between two layers as d Ao, following graphical study was observed when varying θ at different λ.What is the value of d?

By using Bragg's equation,nλ=2dsin⁡θ where, n=2 (2nd diffraction) λ=dsin⁡θ or log⁡λ=log⁡d+log⁡sin⁡θd is constant (distance between two planes) as θ changes, λ also changes.When θ = 90°, sin = 90° = 1, hence log sin 90° = 0OX = 0.3010 Ao∴ log λ = 03012 Ao ∴ λ = 2.0 Ao