Question

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

• A. 1.612
• B. 2
• C. 2.28
• D. 4

Answer 1

Answer: (A)

1.612

Answer 2

Given, angle of diffraction $(2 \theta) = 90^{\circ}$
$= 45^{\circ}$
Distance-between two planes, $d = 2.28\,?$
$n = 2$ [$\because$ second order diffraction]
Bragg's equation is
$n \lambda = 2d \, \sin \, \theta$
$2 \times \lambda = 2 \times 2.28 \times \sin \, 45^{\circ}$
$\lambda = 1.612$