KTUYSBeta
Log inSign up

Cheat sheet · JEE Preparation Physics

Wave Optics cheat sheet

The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.

JEE · Physics

Cheat sheet

Class 12 · Chapter 10Wave Optics

YDSE fringe width β = λD/d.

1. Huygens' Principle

Every point on a wavefront is a source of secondary wavelets; the new wavefront is their envelope. Explains reflection and refraction.

2. Interference (YDSE)

β=λDd\beta = \dfrac{\lambda D}{d}
Δx=nλ\Delta x = n\lambda (bright)Δx=(2n−1)λ2\Delta x = (2n - 1)\dfrac\lambda2 (dark)

Needs coherent sources.

3. Diffraction

asin⁡θ=nλa\sin\theta = n\lambda (minima)
Width of central max=2λDa\text{Width of central max} = \dfrac{2\lambda D}{a}

4. Polarisation

I=I0cos⁡2θI = I_0\cos^2\theta (Malus)tan⁡iB=μ\tan i_B = \mu (Brewster)

Only transverse waves can be polarised.

5. Key Points

  • Fringe width ∝ λ.
  • In water, fringes become narrower (λ/μ).
  • Resolving power improves with larger aperture.
  • Polaroids: sunglasses, 3-D films.

Remember: Huygens | β = λD/d | single slit | Malus & Brewster

Wave Optics: questions and notes

More JEE Preparation Physics cheat sheets

Practise Wave Optics

Sign up free to practise the full chapter. Questions you get wrong come back until you've mastered them.

Start practising free

Free to start · No credit card needed