//Chapter-1,Example 1_31,Page 1-51
clc()


//Condition for bright band is
//2ut*cos r = (2n-1)*lam1

//for consecutive bands, 2n=(lam1+lam2)/(lam1-lam2).
//thus, 2ut*cos r = lam2*lam1/(lam1-lam2)

//And, thicknessof film 
//t= lam2*lam1/((2*u*cosr)(lam1-lam2))
printf('Hence expression for thickness of film is obtained.')