What is the minimum (non-zero) thickness t of the film that produces a strong reflection for green light with a wavelength of 500 nm ?.

What are the two main ideas of this passage? museum experts feel that museums must change to attract visitors. museum experts care more about the number of visitors than about history. museums that display artworks and exhibits do not make families welcome. museums like colonial williamsburg make learning about the past fun. museums in the united states are different than in other countries.