The exiting ray of the center wavelength is thus not only undeviated from the incident ray, but also experiences no translation ( i . e . transverse displacement or offset ) away from the incident ray's path.
2.
Where v ( x ) is the force constant per unit length [ units force per area ] \ omega ^ 2 are the eigenvalues for resonances of transverse displacement \ rho ( x ) on the string ., with solutions that include the various harmonics on a stringed instrument.
3.
The device he designed, later known as a Michelson interferometer, sent yellow light from a sodium flame ( for alignment ), or white light ( for the actual observations ), through a interference whose transverse displacement would depend on the relative time it takes light to transit the longitudinal " vs . " the transverse arms.