NEET 2026 (Phase 1) · PhysicsPrevious Year Question
In a concave lens, a ray of light emanating from the object parallel to the principal axis of the lens, after refraction:
- A.passes through 2F, which is the radius of curvature of the lens.
- B.appears to diverge from the first principal focus.✓
- C.emerges parallel to the principal axis.
- D.passes through the second principal focus.
Correct Answer
(B) appears to diverge from the first principal focus.
Solution & Explanation
Answer: (B) appears to diverge from the first principal focus Solution: A concave (diverging) lens bends a ray that arrives parallel to the principal axis so that it diverges; on projecting the emergent ray backwards it appears to come from a focal point on the incidence side. The official key marks option (B). Note (ERRATA): by NCERT sign convention this focal point — the one from which a parallel incident ray appears to diverge — is properly named the SECOND (incident-side) principal focus, not the first; the keyed wording is retained here as per the official answer.
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