Chromatic aberration will be absent if for two thin lenses in contact :-

Question

G1 Physics · Accepted Answer

Derived solution: Step 1: For thin prisms/lenses use dispersion relations. For an achromatic doublet, ω₁P₁ + ω₂P₂ = 0, while the net power is P₁ + P₂. Step 2: Substitute the values given in the question and apply the geometry/sign convention shown. Step 3: On simplification the result is ω₁/F₁ + ω₂/F₂ = 0. Therefore the correct option is A.