What is the physical interpretation of $\oint \mathbf{A} \cdot d\mathbf{l}$? 1. The current density $\mathbf{J}$ 2. The magnetic field $\mathbf{B}$ 3. The magnetic flux $\Phi_B$ 4. It's none of the above, but is something simple and concrete 5. It has no particular physical interpretation at all Note: * CORRECT ANSWER: C

Consider a square loop enclosing some amount of magnetic field lines with height $H$ and length $L$. We intend to compute $\Phi_B = \oint \mathbf{A} \cdot d\mathbf{l}$? What happens to $\Phi_B$ as $H$ becomes vanishingly small? 1. $\Phi_B$ stays constant 2. $\Phi_B$ gets smaller but doesn't vanish 3. $\Phi_B \rightarrow 0$ Note: * CORRECT ANSWER: C

Consider a square loop enclosing some amount of magnetic field lines with height $H$ and length $L$. If $\Phi_B \rightarrow 0$ as $H \rightarrow 0$ (or $L \rightarrow 0$), what does that say about the continuity of $\mathbf{A}$? $\Phi_B = \oint \mathbf{A} \cdot d\mathbf{l}$ 1. $\mathbf{A}$ is continuous at boundaries 2. $\mathbf{A}$ is discontinuous at boundaries 3. ???

The leading term in the vector potential multipole expansion involves: $\oint d\mathbf{l}'$ What is the magnitude of this integral? 1. $R$ 2. $2\pi R$ 3. 0 4. Something entirely different/it depends! Note: * CORRECT ANSWER: C

<img src="./images/magnetic_dipole_oriented.png" align="left" style="width: 300px";/> Two magnetic dipoles $m_1$ and $m_2$ (equal in magnitude) are oriented in three different ways. Which ways produce a dipole field at large distances? 1. None of these 2. All three 3. 1 only 4. 1 and 2 only 5. 1 and 3 only Note: * CORRECT ANSWER: E