Question

Minimum interplanar spacing required for Bragg's diffraction is -

• A. $\lambda /4$
• B. $\lambda /2$
• C. $\lambda$
• D. $2\lambda$

Answer 1

The correct option is B $\lambda /2$

From Bragg's Law,

$2d\sin \varphi =n\lambda$

$\Rightarrow d=\frac{n\lambda }{2\sin \varphi }$

For minimum value of interplanar spacing $\left(d\right)$, $n=1\left(\text{Minimum value}\right)$ and $\sin \varphi =1\left(\text{Maximum value}\right)$

$\Rightarrow d=\frac{\lambda }{2}$

​​​​​​​Hence, option $\left(B\right)$ is the correct answer.