What is the wavelength of x-ray, if the interplanar distance of the crystal is 286 pm and the incident angle is 15.8o. Order of reflection is 2.
77.8 pm
So, here we have been given interplanar distance (d) = 286 pm and incident angle (ɵ) which is 15.8o We want wavelength of x-ray.
→ Use Bragg’s equation.
nλ=2d sin θ
If the order of reflection is not given,
take n = 1
But here order of reflection is second order.
Therefore n = 2.
nλ=2d sin θ
→2×λ=2×286×10−12×sin(15.8o)→λ=2×286×10−12×0.2722=77.792×10−12 m≃77.8 pm