Dual Nature of Radiation and Matter ā Class 12 CBSE Physics revision notes
A 5-page visual revision sheet for Dual Nature of Radiation and Matter, 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
Dual Nature of Radiation and Matter in one look
light behaves like a particle, matter behaves like a wave: the same duality, seen from both sides
- Photon energy: a packet, not a spread-out wave
- Work function: the least energy to free an electron
- Max kinetic energy: whatever the photon leaves over
Electron emission: three ways out
- free electrons move inside a metal but cannot leave on their own
- leaving costs the work function Ļ_0 (the wall, W in the figures)
- thermionic: heat the metal, a few electrons gain enough to climb out
- field emission: a strong field thins the barrier, electrons slip through
- photoelectric: one photon gives all its energy to one electron
- a photon with less than Ļ_0 frees none: the electron falls back
How strongly heat and field matter
- thermionic current Jā T^2e^-W/kT: almost nothing until the metal is hot
- a lower work function gives far more current at the same temperature
- field emission needs no heating but a field of about 10^8 V/m
- in a hot or field-fed metal the electrons leave with little energy; a photon can give much more
Page 1 of 5. The full sheet, all 5 pages, opens free in the app.
What this Dual Nature of Radiation and Matter sheet covers
- Photon energy
- Work function
- Max kinetic energy
- Electron emission: three ways out
- How strongly heat and field matter
- The photoelectric effect, observed
- Einstein's photoelectric equation
- energy balance
- work function and threshold frequency
- stopping potential
- Brightness and the stopping potential
- What raises current vs what raises stopping potential
- Raise the intensity
- Raise the frequency
- Particle nature of light: the photon
- The photon's energy and momentum
- energy, from frequency or wavelength
- momentum
- a handy form
- Light pushes
- de Broglie waves
- wavelength of any particle of momentum p
- after acceleration through potential V, charge q
- for an electron
- de Broglie wavelength, the special forms
- Davisson and Germer
- Wave-particle duality, both directions
- Symbols
- 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 Dual Nature of Radiation and Matter the sheet opens inside the study block itself ā 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.