The Three Key Graphs of the Photoelectric Effect
KE_max vs ν O ν_{0} ν KE slope=h $V_{0}$ vs ν O ν_{0} ν $V_{0}$ slope=h/e I vs V −$V_{0}$ V I $I_{1}$ (high) $I_{2}$ (low) Same $V_{0}$ Three fundamental graphs of the photoelectric effectComparison: Radiation as Particle vs Matter as Wave
| Feature | Photon (Radiation as Particle) | de Broglie Wave (Matter as Wave) |
|---|---|---|
| Core equation | E = hν; p = h/λ | λ = h/mv = h/p |
| Experimental proof | Photoelectric effect, Compton effect | Davisson-Germer electron diffraction |
| Rest mass | Zero | Non-zero (m_e, m_p, etc.) |
| Speed | Always c | Less than c |
| Controlling variable | Frequency ν | Momentum p = mv |
| NEET shortcut | E(eV) = 1240/λ(nm) | λ_e(nm) = 1.227/√V |
Work Functions of Common Metals (for reference)
| Metal | Work Function φ (eV) | Threshold λ_{0} (nm) | Region |
|---|---|---|---|
| Caesium (Cs) | 2.0 | 620 | Visible (red) |
| Sodium (Na) | 2.3 | 539 | Visible (green) |
| Aluminium (Al) | 4.1 | 302 | UV |
| Copper (Cu) | 4.5 | 276 | UV |
| Platinum (Pt) | 5.7 | 218 | Deep UV |