What type of wavefront emerges from a convex lens when a plane wave is incident on it?
**Wavefront** is locus of points in same phase, spherical from point source, plane at large distance because radius large, Huygens principle every point on wavefront acts as secondary source of wavelets, new wavefront envelope of secondary wavelets, allows prediction of new wavefront shape from known wavefront, explains reflection and refraction. A plane wave incident on a convex lens produces a spherical wavefront converging to the focal point. Using Δ = d sinθ, y = n λ D/d, a sinθ = n λ, I = I₀ cos²θ, n = c/v, sinC = 1/n, λ' = λ/n and A = 2a cos(φ/2), calculation gives Spherical, illustratin
Ref: NCERT > Physics Book > Wave Optics > Wavefront and Huygens Principle