A beam of 50-keV electrons is directed at a crystal and diffracted electrons are found at an angle of 50* relative to the original beam. What is the spacing of the atomic planes of the crystal?
天同: why n=1 (first order) ?
- 天同Lv 77 年前最愛解答
de Brogie wavelength = 6.63x10^-34/square-root[2 x 50x10^3 x 1.6x10^-19 x 9.1x10^-31] m = 5.49x10^-12 m
Incident angle = 50/2 deg = 25 deg
Hence, 2d.sin(25) = 5.49 x 10^-12 where d is the atomic plane spacing
d = 6.5 x 10^-12 m
2013-10-22 23:13:20 補充：
Your suppl question.
It is because n=1 is the FIRST POSSIBLE solution.