NEET UG 2019 · Physics · Question 11
NEET 2019 Physics, question 11
Question 11 of the NEET 2019 paper (code P1) is a Physics question from Ray Optics and Optical Instruments. Its idea, Liquid Trapped Between Two Lenses, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 2.
Updated 2026-10-08
Q11 · Physics
Two similar thin equi-convex lenses, of focal length f each, are kept coaxially in contact with each other such that the focal length of the combination is . When the space between the two lenses is filled with glycerin (which has the same refractive index (μ = 1.5) as that of glass) then the equivalent focal length is . The ratio will be :
- 12 : 1
- 21 : 2Official answer
- 32 : 3
- 43 : 4
Official answer: option 2 · NTA final answer key
Same idea
The only question on Liquid Trapped Between Two Lenses
No other NEET paper from 2017–2026 tested this exact idea.
Liquid Trapped Between Two Lenses: every question and how it was framed
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.