Question
Shankar’s Quantum Mechanics compares this phenomenon to an ideal laugh track, which causes others to laugh alongside it. For 10 points each:
[10m] Name this phenomenon which produces coherent photons and which is described with absorption by the Einstein “B” coefficient.
ANSWER: stimulated emission [prompt on atomic emission; do NOT accept or prompt on “spontaneous emission”]
[10e] During stimulated emission, the laser is in a population inversion because the majority of atoms are excited above this state, the lowest energy level for the system.
ANSWER: ground state
[10h] In population inversion, the state has this unusual property in which the entropy increases as the energy decreases. Systems with this property always emit heat, regardless of the surroundings.
ANSWER: negative temperature [accept negative absolute temperature; accept clear knowledge equivalents]
<IC, Physics>
Summary
| 2023 ILLIAC (Cornell) | 2023-10-21 | Y | 4 | 17.50 | 100% | 50% | 25% |
| 2023 ILLIAC (Mainsite) | 2023-10-21 | Y | 8 | 12.50 | 88% | 13% | 25% |
Data
| Cornell Earth | Columbia Ly-α | 0 | 10 | 0 | 10 |
| Cornell Fire | Cornell Wind | 10 | 10 | 0 | 20 |
| Rochester A | RIT | 10 | 10 | 10 | 30 |
| Rochester B | Rochester C | 0 | 10 | 0 | 10 |