Question
Robert Millikan’s oil drop experiment measured the “elementary” value of this quantity, which is the smallest amount of this quantity that can exist on its own. For 10 points each:
[10e] Name this quantity, which is negative 1.602 times 10-to-the-minus-19 coulombs for an electron.
ANSWER: charge [accept elementary charge; prompt on q]
[10m] Conservation of charge is expressed as [read slowly] “the time derivative of charge density plus [this operation] applied to current density equals zero.” Gauss’s law states that this operation applied to the B-field equals zero, implying magnetic monopoles do not exist.
ANSWER: divergence [accept div or del dot or nabla dot; reject “del” or “dot” alone]
[10h] Per Noether’s (“NURR-tuh’s”) theorem, conservation of charge is a consequence of one of these conditions being invariant with respect to a transformation. Another one of these conditions sets the divergence of the vector potential to zero.
ANSWER: gauge [accept gauge invariance or Coulomb gauge]
<Physics>
Summary
| 2024 ACF Winter at UC Berkeley | 2024-11-16 | Y | 3 | 26.67 | 100% | 100% | 67% |
| 2024 ACF Winter at Lehigh | 2024-11-16 | Y | 7 | 18.57 | 100% | 57% | 29% |
| 2024 ACF Winter at Northwestern | 2024-11-16 | Y | 7 | 12.86 | 71% | 43% | 14% |
| 2024 ACF Winter at Ohio State | 2024-11-16 | Y | 6 | 16.67 | 100% | 50% | 17% |
| 2024 ACF Winter at Online | 2024-11-16 | Y | 8 | 11.25 | 88% | 25% | 0% |
| 2024 ACF Winter at Central Florida | 2024-11-16 | Y | 5 | 16.00 | 80% | 60% | 20% |
| 2024 ACF Winter at Oxford | 2024-11-16 | Y | 10 | 16.00 | 100% | 40% | 20% |