Explain how to solve and then solve the following problems:

Problem #3 You would like to photograph a circular diffraction pattern whose central maximum has a 1 cm diameter. You have a helium-neon laser (wavelength of 633 nm) and a 0.12 mm diameter pinhole. How far behind the pinhole you need to place the viewing screen?Problem #4 Soap bubble is a thin film of water surrounded by air, and the colors you see are produced by interference. What visible wavelength of light are strongly reflected from a 390 nm thick wall soup bubble? What color would such soap bubble appear to be