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Chapter 10 · Unit VI — Optics · Physics

RBSE Class 12 Physics Chapter 10 — Wave Optics: Most Repeated Questions (2013–2026)

तरंग प्रकाशिकी — बार-बार पूछे जाने वाले प्रश्न

Last updated: 5 July 2026

Every RBSE Class 12 Physics board paper from 2013 to 2026 for Wave Optics, sorted and tagged so you know exactly which Young's-double-slit, diffraction and Huygens'-principle questions to revise first.

10
Free PYQs
33
Total PYQs
2013–26
Years covered
EN+हिंदी
Both mediums

Top 5 most-repeated RBSE Class 12 Physics PYQs — Wave Optics

Real previous-year questions with the exact RBSE board years they appeared in — each with its full board solution. 5 more high-yield questions — including polarisation and coherent-source questions — are in the free PDF.

01
2 Marks Short Answer

To produce an interference fringe pattern, draw the necessary diagram of Young's double slit experiment. Derive an expression for the fringe width of bright fringes.

व्यतिकरण फ्रिंज प्रतिरूप उत्पन्न करने के लिए यंग द्वि-स्लिट प्रयोग का आवश्यक चित्र बनाइये। प्रदीप्त फ्रिंजो के लिये फ्रिंज चौड़ाई का व्यंजक व्युत्पन्न कीजिए।

🔥 Most repeated · asked 4×
Solution

diagram

Position of fringes (Bright)

x=nλD/d

Central bright, (n=0)

x0=0

First bright, (n=±1)

x1=±λD/d

Second bright, (n=±2)

x2=±2λD/d

Third bright, (n=±3)

x3=±3λD/d

Brights:

0,±λD/d,±2λD/d,±3λD/d,±4λD/d,…

All solved questions for this chapter are in the full RBSE Physics PYQ book.

Appeared in RBSE 2023 2019 2018 2013
02
1 Mark Very Short Answer

Define diffraction of light.

प्रकाश का विवर्तन की परिभाषा लिखिए।

🔁 Repeated · asked 3×
Solution

Diffraction of light is the bending of light waves as they pass around an obstacle or through an aperture

All solved questions for this chapter are in the full RBSE Physics PYQ book.

Appeared in RBSE 2026 2019 2015
03
3 Marks Long Answer

What is a wavefront? Explain the laws of refraction of light on the basis of Huygens' wave theory.

तरंगाग्र किसे कहते है? हाइगेंस के तरंग सिद्धान्त के आधार पर प्रकाश के अपवर्तन नियमों की व्याख्या कीजिए।

🔁 Repeated · asked 2×
Solution

A wave front is the locus of all points in a medium that are vibrating in the same phase

(a) Rarer to Denser:

diagram

To prove: sini/sinr= Constant =v1/v2

Proof: As, ∠BAC=i

∠ACE=r

Now,

sini=BC/AC

Also,

sinr=AE/AC

Dividing (1) & (2)

sini/sinr=BC/AC

sini/sinr=v1t/v2t=v1/v2

sini/sinr=v1/v2

(b) Denser to Rarer:

To prove: sini/sinr=v2/v1= Constant

Proof: ∠BAC=i

∠ACD=r

Also,

sini=AB/OC

sinr=AD/AC

Dividing (1) & (2)

sini/sinr=AB/OC

sini/sinr=v2t/v1t=v2/v1

sini/sinr=v2/v1

All solved questions for this chapter are in the full RBSE Physics PYQ book.

Appeared in RBSE 2020 2017
04
1 Mark Very Short Answer

What are coherent sources?

कला संबद्ध स्रोत किसे कहते हैं?

⚙️ Core concept
Solution

Coherent sources are two or more sources of light that emit continuous light waves of the same frequency (or wavelength) and have a constant phase difference with respect to each other

All solved questions for this chapter are in the full RBSE Physics PYQ book.

Appeared in RBSE 2024 2021
05
4 Marks Very Long Answer

Write any two necessary conditions for interference of light. Obtain the formula for fringe width in Young's double slit experiment.

प्रकाश के व्यतिकरण के लिए कोई दो आवश्यक शर्तें लिखिए। यंग द्रिस्लिट प्रयोग में व्यतिकरण फ्रिंजों की चौड़ाई ज्ञात करने का सूत्र प्राप्त कीजिए। आवश्यक चित्र बनाइए।

⭐ High-weightage derivation
Solution

The two necessary conditions for sustained interference of light are that the sources must be coherent (have a constant phase difference) and they must be monochromatic (emit light of a single wavelength)

Fringe width ( β ):

Distance b/w two consecutive brights and darks

β=(nth bright) -((n-1)th bright )

β=nλD/d-((n-1)λD)/d

β=λD/d

diagram

OR

Write any two necessary conditions for interference of light. Obtain the formula for fringe width in Young's double slit experiment. Draw necessary diagram

All solved questions for this chapter are in the full RBSE Physics PYQ book.

Appeared in RBSE 2021 2018
5 of 10 free questions previewed

The other 5 are in the free PDF — and all 33 previous-year questions for this chapter are in the full book.

Download your free Chapter 10 PDF (10 Questions)

Get 10 hand-picked previous-year questions from Chapter 10. Every question includes the exam year, marks, and repeat count. Instant download—no signup required.

How Wave Optics is examined in RBSE

A quick map of the chapter before you download — so you know what the questions are testing.

Reviewed by the BoardZone Physics Team — RBSE Class 12 curriculum specialists

If you have gone through the last decade of RBSE Class 12 Physics papers, you will notice Chapter 10 (Wave Optics) is tested every year without fail. It belongs to Unit VI — Optics and is drawn from a pool of 33 previous-year questions spanning 2013–2026, spread across MCQs, very short, short and long-answer sections. The topics rotate, but the question patterns stay remarkably steady.

Expect 1-mark openers defining diffraction, coherent sources, or wavefront. The 1.5 to 2-mark questions lean on Huygens' explanation of refraction. The heavy marks sit in the 2 to 4-mark questions, which almost always ask you to draw Young's double-slit experiment and derive the fringe-width expression — RBSE's most repeated question from this chapter.

So the smart way to revise this chapter is not to read it end to end, but to practise the questions RBSE actually repeats. The five questions above — and the ten in the free sample PDF — are taken straight from real board papers and tagged with the exact years they appeared, so you can see for yourself what the full RBSE Physics chapterwise PYQ book offers before you decide to buy it.

Topics Covered in Wave Optics (Chapter 10)

The RBSE syllabus sub-topics this chapter's PYQs are drawn from — useful for scoping your revision even if you're not buying the full book.

  • ✓ Huygens' principle
  • ✓ Interference and Young's double-slit experiment
  • ✓ Diffraction of light
  • ✓ Polarisation of light
RBSE · PHYSICS · CH.10
FREE SAMPLE

What you get in the free PDF

  • ✓ 10 real RBSE PYQs from Wave Optics
  • ✓ Every question tagged with year and marks weightage
  • ✓ Repeat-frequency tags so you revise the highest-yield questions first
  • ✓ Available in Hindi and English
  • ✓ A 10% off coupon toward the full book

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What's inside this chapter in the full book

The ₹59 full book unlocks all 33 tagged previous-year questions for Wave Optics — plus all 13 other chapters.

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All 33 real PYQs

Every MCQ, VSA, SA and long-answer question for this chapter from RBSE papers 2013–2026 — 33 in total.

🏷️

Tagged & sorted

Each question labelled with year, marks and question type.

🔥

Repeat-priority order

Highest-repeated questions listed first so revision time is spent well.

🇮🇳

Hindi + English

Full bilingual coverage — study in whichever medium you write your exam.

➗

Formula sheet

Quick-reference sheet of every wave optics formula — fringe-width, Huygens' principle and diffraction-pattern formulas.

📅

2026–27 edition

Updated to the latest RBSE board pattern, with access valid for the current 2026–27 exam session.

Frequently asked questions

The most-repeated question in this chapter is 'To produce an interference fringe pattern, draw the necessary diagram of Young's double slit experiment. Derive an expression for the fringe width of bright fringes.' (asked in RBSE 2013, 2018, 2019, 2023). It's followed by 'Define diffraction of light.' RBSE (Rajasthan Board of Secondary Education) repeats these patterns closely each year — our free PDF tags every question with its exact repeat count.
Yes. Wave Optics is a core topic in Unit VI — Optics and is tested every year through MCQs, very short, short and long-answer questions in the RBSE Class 12 Physics board paper.
The full RBSE Class 12 Physics Chapter 10 (Wave Optics) question bank has 33 previous-year questions from 2013 to 2026 — MCQs, very short, short and long-answer. The free sample PDF gives you 10 of them; the full book has all 33.
Yes. When you request the PDF, choose English, Hindi, or Both — the free sample and the full book are available in both mediums, so you can revise in whichever language matches your school textbook and RBSE board exam medium.
10 real RBSE previous-year questions from this chapter (out of 33 total), each tagged with year, marks, and repeat frequency. Questions only — no solutions — so you can self-test before checking the full solved chapter.
No account or email signup is needed. Just share your name and phone number and the PDF is available to download instantly — no payment and no waiting. Your number is only used to send the download link.

All 14 chapters — RBSE Class 12 Physics

01Electric Charges and Fields
विद्युत आवेश तथा क्षेत्र
 02Electrostatic Potential and Capacitance
स्थिरवैद्युत विभव तथा धारिता
 03Current Electricity
विद्युत धारा
 04Moving Charges and Magnetism
गतिमान आवेश तथा चुंबकत्व
 05Magnetism and Matter
चुंबकत्व एवं द्रव्य
 06Electromagnetic Induction
वैद्युतचुंबकीय प्रेरण
 07Alternating Current
प्रत्यावर्ती धारा
 08Electromagnetic Waves
वैद्युतचुंबकीय तरंगें
 09Ray Optics and Optical Instruments
किरण प्रकाशिकी एवं प्रकाशिक यंत्र
 10Wave Optics
तरंग प्रकाशिकी
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विकिरण तथा द्रव्य की द्वैत प्रकृति
 12Atoms
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नाभिक
 14Semiconductor Electronics
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