NEET UG · Physics · Wave Optics

Young's Double Slit: NEET previous year questions

7 questions in ten years of NEET, in 7 of 10 papers. Pattern: Every year. Here is how it is asked and which ideas come back.

Asked in 10 years: 7; about 0.7 per paper
Years asked: 7/10; last asked 2024
Chance of a question next paper: 50%; historical rate, how we compute it
Weighted estimate: 0.5; model; history: 0.7 a paper on average, typically 0–1

Key findings

01
Asked in 7 of 10 papers, 7 questions in all: #124 of 204 topics by ten-year total. It comes back every 1.2 years on average. Last asked in 2024.
02
83% of its questions since 2018 tested an idea never asked before; none repeated an idea from the year before.
03
The most repeated idea is Angular Fringe Width, asked 2 times (2018, 2023), usually as “change in fringe angular width with slit separation”.
04
NEET has asked 6 of the 85 ideas in this topic; 78 have never been asked, directly or indirectly.
05
Mostly asked as numerical (57%); 43% easy, 0% hard, and down from 0.8 to 0.3 questions a paper since 2024.

Questions per year

Up to 2023: 0.8; per paper
Since 2024: 0.3; -0.5
Usual gap: 1.2 yrs; between papers asking it
Swing: ±0.4; questions, year to year

How it is asked

Difficulty, format and skill

Across all 7 questions on Young's Double Slit since 2017.

Difficulty

QUESTIONS

Easy3 · 43%
Medium4 · 57%
Hard0 · 0%

Format

Numerical · 4 Q57%
One-line MCQ · 2 Q29%
Two statements · 1 Q14%

Skill tested

Calculation · 3 Q43%
Concept · 2 Q29%
Application · 2 Q29%

Repeats

New idea, or one asked before?

Each column is a paper. Blue questions tested an idea NEET had not asked before; navy ones went back to an idea from an earlier paper. 2017 is the first paper, so everything in it counts as new.

’17’18’19’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier paper

Coverage of the topic

NEET has asked 6 of the 85 ideas in this topic. 78 have never been asked yet.

Asked directly6 · 7%
Touched inside another question1 · 1%
Never asked78 · 92%

Ideas come from Lumi’s syllabus map of NCERT. A never-asked idea is not a safe skip: most new questions come from exactly these.

Drill down

Idea, year, question

Every idea NEET tested in this topic, with its ten papers. Open one to read the questions.

ideaAskedShareYears’17’18’19’20’21’22’23’24’25’26

Repeated2 · 29%29%2/10
- 2023 · Q24
  For Young's double slit experiment, two statements are given below: Statement I : If screen is moved away from the plane of slits, angular…
  mediumTwo statements
- 2018 · Q9
  In Young's double slit experiment the separation d between the slits is 2 mm, the wavelength $\lambda$ of the light used is 5896 Å and…
  mediumNumericalNew idea
1 · 14%14%1/10
1 · 14%14%1/10
1 · 14%14%1/10
1 · 14%14%1/10
1 · 14%14%1/10

Squares are the ten papers, 2017 to 2026; darker means more questions. Share is of the level above.

Ideas

Every idea inside this topic

6 different ideas were tested; 1 came more than once. Fringe Width Calculation is the foundation for 31 other ideas in the syllabus.

Angular Fringe Width2×
change in fringe angular width with slit separation
Numerical · 6% next · foundation for 1
YDSE with White Light1×
true statement selection on ydse with white light
One-line MCQ · 6% next · foundation for 2
Fringe Width Calculation1×
change in fringe count with wavelength
Numerical · 4% next · foundation for 31
Proportionality of Fringe Width to D and d1×
change in fringe width with slit separation and screen distance
One-line MCQ · 4% next
Effect of Medium on Fringes1×
numerical
Numerical · 4% next
Position of nth Fringe1×
numerical
Numerical · 4% next · foundation for 13

Idea	Times	Format	Chance next	Foundation for
Angular Fringe Widthchange in fringe angular width with slit separation	2	NumericalCalculation	6%	1 ideas
YDSE with White Lighttrue statement selection on ydse with white light	1	One-line MCQConcept	6%	2 ideas
Fringe Width Calculationchange in fringe count with wavelength	1	NumericalApplication	4%	31 ideas
Proportionality of Fringe Width to D and dchange in fringe width with slit separation and screen distance	1	One-line MCQApplication	4%	–
Effect of Medium on Fringesnumerical	1	NumericalCalculation	4%	–
Position of nth Fringenumerical	1	NumericalCalculation	4%	13 ideas

Chance next is the historical rate at which an idea with this record came back in the following paper. It is low for every idea, which is why learning the topic beats memorising past questions. All repeated ideas

Every question

Young's Double Slit questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested.

NEET 20241 question

Q12
If the monochromatic source in Young's double slit experiment is replaced by white light, then
Idea: YDSE with White Light
New ideaEasyOne-line MCQ

NEET 20231 question

Q24
For Young's double slit experiment, two statements are given below: Statement I : If screen is moved away from the plane of slits, angular…
Idea: Angular Fringe Width
MediumTwo statements

NEET 20221 question

Q15
In a Young's double slit experiment, a student observes 8 fringes in a certain segment of screen when a monochromatic light of 600 nm…
Idea: Fringe Width Calculation
New ideaMediumNumerical

NEET 20201 question

Q165
In Young's double slit experiment, if the separation between coherent sources is halved and the distance of the screen from the coherent…
Idea: Proportionality of Fringe Width to D and d
New ideaEasyOne-line MCQ

NEET 20191 question

Q5
In a double slit experiment, when light of wavelength 400 nm was used, the angular width of the first minima formed on a screen placed 1 m…
Idea: Effect of Medium on Fringes
New ideaEasyNumerical

NEET 20181 question

Q9
In Young's double slit experiment the separation d between the slits is 2 mm, the wavelength $\lambda$ of the light used is 5896 Å and…
Idea: Angular Fringe Width
New ideaMediumNumerical

NEET 20171 question

Q14
Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the…
Idea: Position of nth Fringe
MediumNumerical

Questions from the official NEET UG papers published by NTA (CBSE before 2019). Topic and idea tags, counts and notes are Lumi’s.