Question

For a crystal, the angle of diffraction $\left(2\theta \right)$ is $90$ and the second order line has a $d$ value of $2.28\mathring{A}$. The wavelength (in $\mathring{A}$) of $X$-rays used for Bragg's diffraction is:

• A. $1.612$
• B. $2.00$
• C. $2.28$
• D. $4.00$

Answer 1

The correct option is A $1.612$

The order of diffraction (n) is 2.

$2dsin\theta =n\lambda$

$2\times 2.28sin45=2\times \lambda$

$\lambda =1.612A^o$

Note: $2\theta =90$

$\theta =\frac{90}{2}=45$

Hence, wavelength (in A˚) of X-rays used for Bragg's diffraction is $1.612A^o$