//Chapter-1,Example1_2_9,pg 1-17 u=1.2 //refractive index of oil film t=2*10^-7 //thickness of oil film r=60 //angle of refraction //for destructive interference '2*u*t*cos(r) = (2*n-1)*wavelength/2' wavelength_1=(2*u*t*cosd(r)*2/(2*1-1))*10^10 //for n=1 wavelength_2=(2*u*t*cosd(r)*2/(2*2-1))*10^10 //for n=2 wavelength_3=(2*u*t*cosd(r)*2/(2*3-1))*10^10 //for n=3 //visible range of wavelengths is 4000*10^-10 m to 7000*10^-10 m printf('\n for n=1 wavelength = %.f A.\n',wavelength_1) printf('\n for n=2 wavelength = %.f A.\n',wavelength_2) printf('\n for n=3 wavelength = %.f A.\n',wavelength_3) printf('\n The wavelength will be reflected is wavelength = %.f A.\n',wavelength_1)