1. Sodium atoms emit 2.10 eV photons. What is the frequency of these photons? What is the wavelength? What is their speed in a vacuum?
2. Two sound waves (both having a 1.2 m wavelength) interfere with one another. The path-length difference is 2.4 m. What is the interference condition? Constructive or destructive? Breifly explain.
Is the answer destructive since the path length difference is half the wavelength of the two sound waves?