NEET UG 2026 · Physics · Question 20
NEET 2026 Physics, question 20
Question 20 of the NEET 2026 paper (re-exam) is a Physics question from Ray Optics and Optical Instruments. Its idea, Index Correction on the Optical Bench, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 3.
Updated 2026-10-08
Q20 · Physics
Which of the following measurements require 'index correction' ?
- 1Measurement of resistance of a wire using meter bridge
- 2Measurement of gravitational acceleration using simple pendulum
- 3Measurement of focal length of lenses using optical benchOfficial answer
- 4Measurement of speed of sound using resonance tube
Official answer: option 3 · NTA final answer key
Same idea
The only question on Index Correction on the Optical Bench
No other NEET paper from 2017–2026 tested this exact idea.
Index Correction on the Optical Bench: 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.