A parallel beam of light strikes a piece of transparent glass having cross section as shown in the figure below. Correct shape of the emergent wavefront will be (figures are schematic and not drawn to scale)-

Question

G1 Physics · Accepted Answer

Apply Huygens' principle: the portion of the wavefront passing through greater glass thickness is delayed more. The emergent wavefront must therefore have the curvature shown in Image 1. Option A.