Question

In the powder method of the crystals if the Bragg’s angle is Θ then what is the angle of the cone formed by the diffracted beams?

(a) Θ

(b) 2Θ

(c) 3Θ

(d) 4Θ

I have been asked this question in exam.

This intriguing question comes from The X-ray Diffraction Experiment in section X-Ray Diffraction of Solid State Chemistry

Answer 1

Right answer is (d) 4Θ

The explanation: The diffracted beams in the powder method forms a cone, if the Bragg’s angle is Θ, then the angle between diffracted and undiffracted beams is 2Θ and the angle of the cone is 4Θ. Each set of planes gives its own cone of radiation.