Question

What feature appears in the emerging wavefront of a plane wave passing through a thin convex lens?

विकल्प

• The greatest thickness of glass in the lower portion

• A depression at the centre

• A tangent plane CE

• A tilt in the emerging wavefront

Answer 1

The centre of the wavefront is delayed more than its other parts. This unequal delay produces a depression at the centre of the emerging wavefront.