4 A plane wave AB is incident at an angle i on the surface
PP¢  separating medium 1 and medium 2 The plane wave undergoes
refraction and CE represents the refracted wavefront The figure
corresponds to v2 < v1 so that the refracted waves bends towards the
normal Rationalised 2023-24
259
Wave Optics
In order to determine the shape of the refracted
wavefront, we draw a sphere of radius v2t from the point
A in the second medium (the speed of the wave in the
second medium is v2)