JEE Main · Physics · Ray Optics and Optical Instruments
Optical Instruments: JEE Main previous year questions
13 questions in the 108 JEE Main shifts Lumi analysed, in 5 of 8 years. Pattern: Asked most years. 2 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 13
- in 12 of 108 shifts
- Years asked
- 5/8
- last asked 2026
- Weighted estimate
- 0.1
- model; history: 0.1 a shift on average, typically 0.0–0.2
Key findings
- 01
Asked in 5 of 8 years with analysed shifts and in 12 of 108 shifts: 13 questions, #168 of 196 topics. The years that asked it were 1.5 apart on average.
- 02
85% of its questions since 2020 tested an idea no earlier year had asked; 1 repeated an idea from the year before.
- 03
The most repeated idea is Microscope Tube Length, asked 2 times in 2 shifts (2020, 2026), most often as “change in tube length for same magnification”.
- 04
JEE Main has asked 11 of the 54 ideas in this topic; 40 have never been asked, directly or inside another question.
- 05
Mostly asked as single correct (77%); 15% need a numerical answer, 46% are easy and 15% hard.
- 06
The skill tested most is calculation (46%), then conceptual (23%).
Questions a shift, year by year
Out of the 25 Physics questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.
Raw count: 2017: 0 in 1 shift · 2020: 3 in 12 shifts · 2021: 5 in 24 shifts · 2022: 2 in 24 shifts · 2023: 1 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 2 in 9 shifts.
- Up to 2023
- 0.1
- a shift, of 25
- Since 2024
- 0.1
- 0.0
- Usual gap
- 1.5 yrs
- between years asking it
- Shifts with it
- 12/108
- 11% of analysed shifts
How it is asked
Difficulty, format and skill
Across all 13 questions on Optical Instruments since 2017.
Difficulty
QUESTIONS- Easy6 · 46%
- Medium5 · 38%
- Hard2 · 15%
Format
SHARE- Single correct · 10 Q77%
- Numerical value · 2 Q15%
- Assertion–reason · 1 Q8%
Skill tested
SHARE- Calculation · 6 Q46%
- Conceptual · 3 Q23%
- Multi-step · 2 Q15%
- Recall · 1 Q8%
- Application · 1 Q8%
Repeats
New idea, or one asked before?
Each column is a year. Blue questions tested an idea no earlier year had asked; navy ones went back to an idea from an earlier year. 2017 is the first year, so everything in it counts as new. Heights are question counts, and Lumi analysed 1 to 24 shifts a year, so compare the split inside a column rather than heights across years.
- Idea asked for the first time
- Idea asked in an earlier year
Coverage of the topic
JEE Main has asked 11 of the 54 ideas in this topic. 40 have never been asked yet.
- Asked directly11 · 20%
- Touched inside another question3 · 6%
- Never asked40 · 74%
Ideas come from Lumi’s JEE syllabus map. A never-asked idea is not a safe skip: across all of JEE Main, 22% of questions since 2024 tested an idea no earlier year had asked.
Drill down
Chapter, idea, question
Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.
10 ideas inside
Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.
Ideas
Every idea inside this topic
11 different ideas were tested; 2 came more than once.
change in tube length for same magnification
Numerical value · 2 shifts · 1 numericalobjective magnification from compound microscope magnification
Numerical value · 2 shifts · 1 numericaltelescope aperture from resolution limit
Single correct · 1 shiftpurpose of secondary mirror in reflecting telescope
Single correct · 1 shifttelescope focal length from magnification
Single correct · 1 shiftresolving power change on oil immersion
Single correct · 1 shiftidentify eye defect from symptoms
Single correct · 1 shiftspectacle lens for defective near point
Single correct · 1 shiftpower of microscope from angular magnification
Single correct · 1 shiftassertion-reason on simple microscope
Assertion–reason · 1 shifteyepiece focal length from tube length
Single correct · 1 shift
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Microscope Tube Lengthchange in tube length for same magnification | 2 | 2 | Numerical valueCalculation | 1 | |
| Compound Microscope Magnificationobjective magnification from compound microscope magnification | 2 | 2 | Numerical valueCalculation | 1 | |
| Resolving Powertelescope aperture from resolution limit | 1 | 1 | Single correctCalculation | – | |
| Reflecting Telescopespurpose of secondary mirror in reflecting telescope | 1 | 1 | Single correctRecall | – | |
| Astronomical Telescope Magnificationtelescope focal length from magnification | 1 | 1 | Single correctCalculation | – | |
| Numerical Aperture and Oil Immersionresolving power change on oil immersion | 1 | 1 | Single correctConceptual | – | |
| Astigmatism and Cylindrical Lensesidentify eye defect from symptoms | 1 | 1 | Single correctConceptual | – | |
| Hypermetropia Correctionspectacle lens for defective near point | 1 | 1 | Single correctApplication | – | |
| Simple Microscope Magnificationpower of microscope from angular magnification | 1 | 1 | Single correctCalculation | – | |
| Visual Angle and Angular Magnificationassertion-reason on simple microscope | 1 | 1 | Assertion–reasonConceptual | – | |
| Telescope Tube Lengtheyepiece focal length from tube length | 1 | 1 | Single correctCalculation | – |
Times and shifts count every analysed shift. Across JEE Main, 78% of questions since 2024 went back to an idea an earlier year had asked; the rest were new. All repeated ideas
Every question
Optical Instruments questions, year by year
The opening words of each question as it appeared in the official paper, with the idea it tested. Open one for its options and the official answer.
JEE Main 20262 questions in 2 shifts
- 4 Apr, Shift 1Q44A telescope with objective diameter is used to observe a distant star emitting light of wavelength nm, at a resolution of…
Idea: Resolving Power
New ideaEasySingle correct - 5 Apr, Shift 1Q42A compound microscope is designed with two symmetric biconvex lenses. The objective lens is cut vertically, creating two identical…
Idea: Microscope Tube Length
HardSingle correct
JEE Main 20231 question in 1 shift
- 8 Apr, Shift 1Q45In a reflecting telescope, a secondary mirror is used to:
Idea: Reflecting Telescopes
New ideaEasySingle correct
JEE Main 20222 questions in 2 shifts
- 27 Jul, Shift 1Q46A microscope was initially placed in air (refractive index 1). It is then immersed in oil (refractive index 2). For a light whose…
Idea: Numerical Aperture and Oil Immersion
New ideaMediumSingle correct - 28 Jul, Shift 1Q46In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm. The focal length of the…
Idea: Astronomical Telescope Magnification
New ideaEasySingle correct
JEE Main 20215 questions in 4 shifts
- 3 Aug, Shift 1Q17A compound microscope has a magnification of 30. Assuming that the final image is formed at the least distance of distinct vision (25…
Idea: Compound Microscope Magnification
Asked the year beforeMediumSingle correct - 3 Aug, Shift 2Q15To view a small object with angular magnification 5, the power of the microscope needed is [The final image is formed at infinity]…
Idea: Simple Microscope Magnification
New ideaEasySingle correct - 3 Aug, Shift 2Q16If a man having the least distance of distinct vision of 50 cm, what should be the focal length of the spectacles for the man ?
Idea: Hypermetropia Correction
New ideaEasySingle correct - 26 Feb, Shift 2Q2Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R. Assertion A : For a simple…
Idea: Visual Angle and Angular Magnification
New ideaMediumAssertion–reason - 18 Mar, Shift 1Q16Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as non-uniform…
Idea: Astigmatism and Cylindrical Lenses
New ideaMediumSingle correct
JEE Main 20203 questions in 3 shifts
- 8 Jan, Shift 1Q16The magnifying power of a telescope with tube length 60 cm is 5. What is the focal length of its eye piece ?
Idea: Telescope Tube Length
New ideaEasySingle correct - 4 Sep, Shift 1Q24In a compound microscope, the magnified virtual image is formed at a distance of 25 cm from the eye-piece. The focal length of its…
Idea: Compound Microscope Magnification
New ideaHardNumerical value - 5 Sep, Shift 1Q24A compound microscope consists of an objective lens of focal length 1 cm and an eye piece of focal length 5 cm with a separation of 10 cm.…
Idea: Microscope Tube Length
New ideaMediumNumerical value
Questions from the official JEE Main Paper 1 shifts published by NTA (CBSE for 2017). Questions NTA dropped are left out. Topic and idea tags, counts and notes are Lumi’s.