Wave Optics — Class 12 CBSE Physics revision notes
A 5-page visual revision sheet for Wave Optics, written for Class 12 CBSE Physics. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Wave Optics in one look
light interferes, diffracts and polarises: the wave picture ray optics never needed
- Wavefront: every point on it is a fresh source of secondary wavelets
- Envelope: the common tangent to all the wavelets, one time-step later
- New wavefront: always perpendicular to the ray direction
Coherence, the condition for a stable pattern
- two sources are coherent when they keep a constant phase difference, never drifting apart
- two independent bulbs are never coherent: interference washes out too fast to see
- Young's setup gets coherence for free by splitting one wavefront into two, with a double slit
Young's double slit
- path difference at a point on the screen
Δ=dsinθapproxdy/D - bright fringe, constructive
Δ=nλ, n=0,±1,±2,... - dark fringe, destructive
Δ=(n+tfrac12)λ - fringe width
β=λ D/d
Page 1 of 5. The full sheet, all 5 pages, opens free in the app.
What this Wave Optics sheet covers
- Wavefront
- Envelope
- New wavefront
- Huygens' construction
- Coherence, the condition for a stable pattern
- Young's double slit
- path difference at a point on the screen
- bright fringe, constructive
- dark fringe, destructive
- fringe width
- The intensity pattern
- Diffraction at a single slit
- first minimum, slit width a
- nth minimum
- angular width of the central maximum
- Interference vs diffraction
- Interference
- Diffraction
- Resolving power
- Rayleigh criterion, limit of resolution
- resolving power of a microscope
- Polarisation
- Malus's law
- intensity after a second Polaroid at angle θ to the first
- crossed Polaroids, θ = 90°
- aligned Polaroids, θ = 0°
- Symbols
- Thin films and coatings
- Air wedge and Newton's rings
- The diffraction grating
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Physics chapter by chapter against your real exam dates and free hours, and when the plan reaches Wave Optics the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.
More Physics Class 12 revision notes
- Alternating Current
- Atoms
- Current Electricity
- Dual Nature of Radiation and Matter
- Electric Charges and Fields
- Electromagnetic Induction
- Electromagnetic Waves
- Electrostatic Potential and Capacitance
- Magnetism and Matter
- Moving Charges and Magnetism
- Nuclei
- Ray Optics and Optical Instruments
- Semiconductor Electronics