Geometrical Optics

The figure shows surface XY separating two transparent media, medium -1 and medium -2 . The lines ab and cd represent wavefronts of a light wave traveling in medium -1 and incident on X Y. The lines ef and gh represent wavefronts of the light wave in medium -2 after refraction.

The phases of the light wave at \(c, d, e\) and \(f\) are \(\phi_c, \phi_d, \phi_{e}\) and \(\phi_{f}\) respectively.

It is given that \(\phi_{c} \neq \phi_{f}\).