🔭 PHYSICS

Optics Made Easy —
Ray & Wave Optics in 7 Days

👨‍🏫 By Abhishek Gupta Sir, IIT Delhi📅 Dec 15, 2024⏱ 12 min read

Why Optics? Optics = 18 marks in CBSE + 2-3 questions in JEE Main + frequent in JEE Advanced. If you master Optics, you secure 18 marks before entering the exam hall. This 7-day plan works.

📅 The 7-Day Optics Mastery Plan

Day 1

Reflection — Mirrors

Concave vs Convex mirror. Mirror formula: 1/v + 1/u = 1/f. Sign convention is critical — get this wrong and everything fails. Practice 10 numericals.

Day 2

Refraction at Plane Surface

Snell's Law, Total Internal Reflection, Critical Angle. TIR applications — optical fibre, diamond. 8 numericals.

Day 3

Refraction at Curved Surfaces & Lenses

Lens Maker's Formula — derivation is compulsory for boards. Power of lens. Combination of lenses. 12 numericals.

Day 4

Optical Instruments

Human eye — defects and correction. Microscope and Telescope — ray diagrams are mandatory. Learn to draw neat diagrams quickly.

Day 5

Wave Optics — Huygens Principle

Wavefront concept, Huygens construction. Laws of reflection and refraction using wave theory. YDSE — complete derivation.

Day 6

Interference & Diffraction

YDSE formulas — fringe width, maxima/minima conditions. Single slit diffraction — central maximum width. Polarisation.

Day 7

Revision + Mixed Practice

Solve 20 mixed Optics questions. Include 5 JEE Main PYQs and 1 CBSE sample paper Optics section. Time yourself.

🔑 Key Formulas — Never Forget

Reflection

Mirror Formula

1/v + 1/u = 1/f

Refraction

Snell's Law

n₁ sin θ₁ = n₂ sin θ₂

Lenses

Lens Formula

1/v - 1/u = 1/f

Wave Optics

YDSE Fringe Width

β = λD/d

🔭

Learn Optics from Abhishek Sir!

B.Tech Engineering Physics, IIT Delhi | Research Published Internationally | 20+ Years

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Abhishek Gupta Sir (IIT Delhi) teaches JEE, NEET & CBSE Physics at CSS, 56A Naraina Vihar, New Delhi 110028. Near Janakpuri, Tilak Nagar, Punjabi Bagh. Online & Offline.