複選題

18. Which of the following statements are correct?
(A) According to the Bragg's law, when monochromatic X-rays of wavelength $\lambda = 0.154\,\mathrm{nm}$ are incident on the crystal with lattice spacing $d = 0.5\,\mathrm{nm}$, the first-order diffraction angle $\theta$ is approximately $18^{\circ}$.
(B) A spectrometer on Earth with a detection limit of $0.5\,\mathrm{nm}$ can be used to detect the difference between classical and relativistic Doppler's shifts of a star moving toward Earth at a speed of $6\times 10^{6}\,\mathrm{m/s}$ and emitting light at a wavelength of $500\,\mathrm{nm}$.
(C) For a free particle in one dimension with the time-dependent Schrödinger wave function $\psi(x,t) = Ae^{i(kx - \omega t)}$, the probability density is independent of time.
(D) In the Compton scattering, a photon scattered by a free electron will generally emerge with a longer wavelength if it is deflected through a larger angle.
(E) A particle whose wave function is a perfect plane wave has a precisely defined momentum.