Q. The first order reflection $(n = 1)$ from a crystal of the X-ray from a copper anode tube $(\lambda = 1.54\ \mathring{\mathrm{A}})$occurs at an angle of $45{^\circ}.$ What is the distance between the set of plane causing the diffraction?
A) 0.1089 nm
B) 0.1089 m
C) 0.905 $\mathring{\mathrm{A}}$
D) $1.089 \times 10^{- 9}m$
Explanation
(c)
$n\lambda = 2d\ \sin\theta$
$1 \times 1.54\ = \ 2d\ \sin{45{^\circ}}$
$1 \times 1.54\ = \ 2d\ \times \ 0.850$
$\ \ \ \ \ \ \ \ \ \ \ \ 2d = \frac{1.54}{0.850} = 0.905\ \mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.