Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is:
(A)Both spherical and cylindrical
(B)Cylindrical
(C)Spherical
(D)Plane✓ Correct
Answer: (D)
Solution
A point source placed at the focus of a convex lens sends rays out parallel to the principal axis. A parallel beam corresponds to a plane wavefront (wavefronts are surfaces perpendicular to the rays). Hence the emerging light has a plane wavefront.
JEE Main · 2024 · 05 Apr 2024 · Shift 1 · Single correct option