  We explore different facets of the action of linearized gravitational waves
in Minkowski spacetime background upon light, under the electromagnetic
geometrical optics limit, covering the main aspects: light trajectory
perturbations, radar distance and light frequency shift. For this purpose, we
consider observers comoving with the transverse traceless gauge coordinates. We
compute the parametrized null geodesics exchanged between two of these
observers, presenting explicitly the constants of motion as functions of
observables, determining therefrom both the radar distance between the
observers and the electromagnetic round-trip frequency shift caused by the
gravitational wave. Also, a comparison is made between these results and what
one would obtain by using a frequently adopted hybrid model in which the
spatial trajectory of light is unchanged. Finally, we revisit and provide an
explanation, resorting to the constancy of the phase along a light ray, to the
fundamental puzzling question of how one is able to detect gravitational waves
by means of interferometry if both light wavelength and detector arms are
stretched.
