The figure shows a surface XY separting 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 of XY. The lines ef and gh represent wavefronts of the light wave in medium-2 after refraction.
Light travels as a
parallel beam in each medium
convergent beam in each medium
divergent beam in each medium
divergent beam in one medium and convergent beam in the other medium