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// Scilab code Ex8.17: Diffraction of electrons from fcc crystal planes Page 295 (2010)
// Declare a function for converting angle into degrees and minutes
function [d,m] = degree_minute(n)
d = int(n);
m = (n-int(n))*60;
endfunction
h = 6.626e-034; // Planck's constant, Js
m = 9.1e-031; // Rest mass of electron, kg
e = 1.602e-019; // charge on an electron, coulomb
a = 3.5e-010; // Lattice parameter of fcc crystal, m
V = 80; // Accelerating potential for electrons, volt
lambda = h/sqrt(2*m*e*V); // de-Broglie wavelength of electrons, m
d_111 = a/sqrt(3); // Interplanar spacing for (111) planes of fcc crystal, m
// Bragg's equation for first order diffraction (n = 1) is
// lambda = 2*d_111*sind(theta_111); // Bragg's law, m
theta_111 = asind(lambda/(2*d_111)); // Bragg's angle, degree
[deg, mint] = degree_minute(theta_111); // Call conversion function
printf("\nThe Bragg angle for electron diffraction = %d deg %d min", deg, mint);
// Result
// The Bragg angle for electron diffraction = 19 deg 50 min
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