NEET UG 2023 · Physics · Question 45
NEET 2023 Physics, question 45
Question 45 of the NEET 2023 paper (code G6) is a Physics question from Ray Optics and Optical Instruments. Its idea, Lens Maker's Formula, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 4.
Updated 2026-10-08
Q45 · Physics
In the figure shown here, what is the equivalent focal length of the combination of lenses (Assume that all layers are thin)?
The figure, described in words
A biconvex lens of refractive index n1 = 1.5 (surfaces R1 = R2 = 20 cm) set inside a slab of medium n2 = 1.6 filling the region around it, forming two plano-concave layers of n2 on either side.
- 1−50 cm
- 240 cm
- 3−40 cm
- 4−100 cmOfficial answer
Official answer: option 4 · NTA final answer key
Same idea
The only question on Lens Maker's Formula
No other NEET paper from 2017–2026 tested this exact idea.
The chapter
Ray Optics and Optical Instruments in ten years of NEET
26 questions from 2017–2026, asked in 10 of 10 papers, about 2.5 a paper. Thin Lens Formula alone had 9.