//Chapter-2,Example2_6_5,pg 2-34

wavelength=5890*10^-10                                    //wavelength of light 

d_wavelength=6*10^-10

m=2                                                //for second order 

N=wavelength/(d_wavelength*m)

W=3                                              //width of grating

width=W/N

printf('\nNumber of lines is  N = %.0f \n',N)

printf('\n The grating element(width of line) is  a+b =%.7f cm',width)