Answer :
Answer:
Second order line appears at 43.33° Bragg angle.
Explanation:
When there is a scattering of x- rays from the crystal lattice and interference occurs, this is known as Bragg's law.
The Bragg's diffraction equation is :
[tex]n\lambda=2d\sin\theta[/tex] .....(1)
Here n is order of constructive interference, λ is wavelength of x-ray beam, d is the inter spacing distance of lattice and θ is the Bragg's angle or scattering angle.
Given :
Wavelength, λ = 1.4 x 10⁻¹⁰ m
Bragg's angle, θ = 20°
Order of constructive interference, n =1
Substitute these value in equation (1).
[tex]1\times1.4\times10^{-10} =2d\sin20[/tex]
d = 2.04 x 10⁻¹⁰ m
For second order constructive interference, let the Bragg's angle be θ₁.
Substitute 2 for n, 2.04 x 10⁻¹⁰ m for d and 1.4 x 10⁻¹⁰ m for λ in equation (1).
[tex]2\times1.4\times10^{-10} =2\times2.04\times10^{-10} \sin\theta_{1}[/tex]
[tex]\sin\theta_{1} =0.68[/tex]
θ₁ = 43.33°