Question

What causes chromatic aberration?

• A. Non-paraxial rays
• B. Paraxial rays
• C. Variation of focal length with colour
• D. Difference in radii of curvature of the bounding surfaces of the lens

Answer 1

Answer: (C)

In chromatic aberration the image formed by a lens has coloured fringes, because the refracive index for different colours is different and hence the focal length of lens for different colours is different. So, the cause of chromatic aberration is the variation of focal length with colour