Question

If $AB$ is incident wavefront. Then, refracted wavefront is

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

When $ABC$ wavefront passes through glass, its velocity is reduced.

As, points $A$ and $C$ remain in glass for a short duration, they move for a larger distance and $B$ covers a small distance as it remains in glass for a longer duration (middle portion of glass is thick) and finally $A^{\prime }{B}^{\prime }{C}^{\prime }$ is position of new wavefront. It is concave in shape.