MCQ
Bragg’s law for $X-$ rays is
  • A
    $d sin$ $\theta = 2n\lambda $
  • $2d\,\sin \,\theta = n\lambda $
  • C
    $n\sin \theta = 2\lambda d$
  • D
    None of these

Answer

Correct option: B.
$2d\,\sin \,\theta = n\lambda $
b
(b) Suppose, and X-ray bean is incident on a solid, making an angle $\theta$ with the planes of the atoms. These $\mathrm{X}$ -rays are diffracted by different atoms and the diffracted rays interfere. In certain directions, the interference is constructive and we obtain strong reflected $X$ -rays. The analysis shows that there will be a strong reflected $x$ -ray beam only if $2 d \sin \theta=n \lambda$

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