2. Light from a helium-neon laser (I=633nm) illuminates two slits spaced 0.40 apart. A viewing screen is 2.0 m behind the slits. What are the distances between the two m = 3 bright fringes and between the two m = 3 dark fringes? 3. A soap bubble 560nm thick and of refractive index 1.33 is illustrated at near normal incidence by white light. Calculate the wavelengths of the light for which destructive and constructive interferences occur.