// Scilab Code Ex2.18 Energy difference in the emission or absorption of sodium D1 line: Pg:58 (2008)s
h = 6.624e-034;    // Planck's Constant, Js
c = 3e+08;    // Speed of light, m/s
L = 590e-09;    // Wavelenght of sodium D1 line, m
E = h*c/L;    // Energy difference in the emission or absorption of sodium D1 line, J
printf("\nThe energy difference in the emission or absorption of sodium D1 line = %4.2e J", E);
// Result 
// The energy difference in the emission or absorption of sodium D1 line = 3.37e-019 J