Q. Light of wavelength 672nm in vacuum is incident on a single slit whose width is 1.60 × 10-5 m. The setup is then immersed in water whose index of refraction is 1.33. What is the angle θ that locates the third dark fringe regarding the central bright fringe?
Q. You have just built a house out in the country and it comes to your attention that you need to install a lightning rod. Being naturally curious you ask a hardware salesperson how lightning rods work and they accurately tell you.