Question
A consequence of this principle used in antenna engineering states that the product of input impedances of metal and slot pieces equals the square of intrinsic impedance over four. For 10 points each:
[10h] Name this principle that states the pattern formed from an opaque body can be reformulated as a hole of the same size and shape, but with a different beam intensity.
ANSWER: Babinet’s (“bab-in-AY’s”) principle
[10e] Babinet’s principle concerns the patterns formed by this phenomenon in which light bends around an obstacle.
ANSWER: diffraction [accept diffraction patterns]
[10m] Babinet’s principle is formulated for scalar fields using this physicist’s diffraction formula, from which the Huygens–Fresnel (“HIGH-guns fren-EL”) principle is derived. This physicist described the spectra of gases in his three laws of spectroscopy.
ANSWER: Gustav Kirchhoff [or Gustav Robert Kirchhoff; accept Kirchhoff’s diffraction formula or Kirchhoff’s laws of spectroscopy]
<Purdue, Physics>
Summary
| California | 2025-02-01 | Y | 3 | 13.33 | 67% | 33% | 33% |
| Florida | 2025-02-01 | Y | 1 | 20.00 | 100% | 100% | 0% |
| Great Lakes | 2025-02-01 | Y | 5 | 6.00 | 60% | 0% | 0% |
| Lower Mid-Atlantic | 2025-02-01 | Y | 5 | 8.00 | 80% | 0% | 0% |
| Midwest | 2025-02-01 | Y | 6 | 15.00 | 83% | 33% | 33% |
| North | 2025-02-01 | Y | 2 | 10.00 | 100% | 0% | 0% |
| Northeast | 2025-02-01 | Y | 4 | 2.50 | 25% | 0% | 0% |
| Pacific Northwest | 2025-02-01 | Y | 2 | 15.00 | 100% | 50% | 0% |
| South Central | 2025-02-01 | Y | 2 | 20.00 | 100% | 50% | 50% |
| Southeast | 2025-02-01 | Y | 4 | 10.00 | 75% | 25% | 0% |
| Upper Mid-Atlantic | 2025-02-01 | Y | 6 | 10.00 | 83% | 17% | 0% |
| Upstate NY | 2025-02-01 | Y | 2 | 10.00 | 50% | 50% | 0% |
Data
| UNC B | Liberty C | 0 | 10 | 0 | 10 |
| Liberty A | South Carolina | 0 | 0 | 0 | 0 |
| William & Mary | UNC C | 0 | 10 | 0 | 10 |
| Virginia Tech A | UNC D | 0 | 10 | 0 | 10 |
| Virginia A | Duke | 0 | 10 | 0 | 10 |