Light with frequency f is emitted in air from a source S. Light can get reflected back to the source by mirror 1, a distance y from the source or by mirror 2, a distance x from the source (see figure). a) What is the wavelength of the light in air? b) What is the phase difference φ between the light reaching the source back after reflection from mirror 1 and that reaching it after reflection from mirror 2? c) Using part b, write the condition for constructive interference between the two light beams. d) A block of glass, with length L and index of refraction n is placed between the source and mirror 1. What is the wavelength of the light in the glass? e) What is the additional phase shift φ’ introduced by the glass? f) Write the condition for constructive interference in this case (i.e., when you have the path difference AND the glass).