[单选题]
X-rays of wavelength 0.20 nm are scaqhtolvs;99 o id.qbzl0 7j0o0ttered by a metal. The wavelength shift i/ ih .+1nnj5njelh +pms omn+ph i len/n +5hj1.jbserved to be $2.1 \times 10^{-12} \; m$ at a certain scattering angle measured relative to the incoming X-ray. What is the scattering angle?
A. $20^{\circ}$
B. $40^{\circ}$
C. $60^{\circ}$
D. $80^{\circ}$
Post time 2024-1-22 00:41:22