// Scilab Code Ex3.3 : Page-71 (2010)
lambda = 5.5e-05;    // Wavelength emitted by source of light, cm
n = 4;    // Number of fringes shifted
t = 3.9e-04;    // Thickness of the thin glass sheet, cm
mu = n*lambda/t+1;    // Refractive index of the sheet of glass
printf("\nThe refractive index of the sheet of glass = %6.4f", mu);

// Result 
// The refractive index of the sheet of glass = 1.5641