5. A soap film in air has a thickness of 175 nm. If the index of refraction of the soap film is 1.35, what colour of light will be transmitted through? (i.e., What colour does the bubble appear to be from the other side?) 6. A student performs Young's double-slit experiment using a slit separation of 21.6 um. A screen is placed 2.50 m from the centre of the sources such that a point on the fifth nodal line is 37.5 om from the centre of the interference pattern. Find the wavelength of the light used and identify its colour