In the far field, the power radiated from an oscillating one of these systems goes like the square of the sine of the angle from the axis defining this system. For 10 points each:
[10m] Name this arrangement of charges, corresponding to the “L equals 1” spherical harmonics in an expansion of the potential.
ANSWER: electric dipole [prompt on any description of two equal and opposite charges]
[10e] The simplest one of these devices is their ‘half-wave dipole’ type. These devices are used to send and receive electrical signals such as radio waves.
ANSWER: antennas
[10h] For a collection of arbitrarily moving charges and currents, the electric and magnetic fields are given by these equations that represent the retarded time solution to Maxwell’s equations.
ANSWER: Jefimenko’s equations [generously prompt on Lienard-Wiechert by asking “what is the equation for the fields”]