A star is moving at 0.2c along the x axis. The star is moving away from observer A and toward observer B..The star emits light with a maximum intensity at wavelength 500nm.
(a) Calculate the spacing between wave crests for emitted light with ?= 500nm ahead of the star and behind it in the star's frame of reference..
(b) Transform these lengths to the observers' frame of reference.
(c) Calculate the frequency of the light in the star's frame of reference.