1. As seen by an observer on Earth, two stars are separated by an angle of 0.0005. What is the minimum diameter of a telescope required for an Earth astronomer to see two separate stars? (Assume a circular aperture and an average wavelength for the light of 500 nm.) 2. Sound waves of 675 Hz travel at a speed of 345 m/s through a doorway in a soundproof wall. If the doorway is 1.5 m wide, how many "quiet spots" (locations where no sound is heard") will there be along a line parallel to the wall? What will be the angular location of these quiet spots? 3. Young's double slit experiment is performed with visible light of 500 nm. The light projects through two openings separated by a distance of 10.0 mm onto a screen 10.0 m away. How many meters away from the central bright spot is the first order bright spot on the screen? (Or, if there is no first order central bright spot then answer "no first order bright spots are produced".) 4. Suppose the experiment described in problem 3 is performed with radio waves of 500 m instead of light of 500 nm. How many meters away from the central interference maximum is the first order interference maximum? (Or, if there is no first order interference maximum then answer "no first order interference maximum is produced.)