For a crystal, the angle of diffraction $(2 \theta)$ is $90^{\circ}$ and the second order line has a $d$…
For a crystal, the angle of diffraction $(2 \theta)$ is $90^{\circ}$ and the second order line has a $d$ value of $2.28 Ã…$. The wavelength (in $Ã…$ ) of X-rays used for Bragg's diffraction is
$1.612$
$2.00$
$2.28$
$4.00$
Solution
Given, angle of diffraction $(2 \theta)=90^{\circ}$
$
\theta=45^{\circ}
$
Distance between two planes, $d=2.28 Ã…$
$
n=2 \quad[\because \text { second order diffraction }]
$
Bragg's equation is
$
\begin{aligned}
n \lambda & =2 d \sin \theta \\
2 \times \lambda & =2 \times 2.28 \times \sin 45^{\circ} \\
\lambda & =1.612
\end{aligned}
$