# PH632: Electromagnetic Theory II

**Instructor (Winter 2016):**Prof. Ethan Minot**Office:**Weniger 417**Textbook:**See course_info**Class Meetings:**MWF 10:00-10:50, Weniger 377

## Calendar

Week1 | Day | Topic | Reading | Summary | Assignments |
---|---|---|---|---|---|

M 1/4 | Snow day | No class | |||

W 1/6 | Comp exam | No class | |||

1 | F 1/8 | Biot-Savart | day1_2016.pdf: Illustration that electric and magnetic fields are “the same thing”, what you call it depends on your reference frame. How to find B generated by J by considering the differential equation curlB = u0J | hw1 | |

Week2 | Day | Topic | Reading | Summary | Assignments |

2 | M 1/11 | day2_2016.pdf: Current density created by the motion of a charge distribution. Current restricted to thin sheet or thin wire. | |||

3 | W 1/13 | day3_2016.pdf: Relationship be current density and particle flux. Application of Biot-Savart law, infinitely long straight wire. | |||

F 1/15 | Physics Conference | No class | hw1soln_2016.pdf | ||

Week3 | Day | Topic | Reading | Summary | Assignments |

M 1/18 | MLK HOLIDAY | No class | |||

4 | W 1/20 | day4_2016.pdf: Special geometries where Ampere's law can be used. Begin calculating magnetic field far away from a current loop. | hw2 | ||

5 | F 1/22 | day5_2016.pdf: The field generated by a magnetic dipole. | hw2soln_2016.pdf | ||

Week4 | Day | Topic | Reading | Summary | Assignments |

6 | M 1/25 | day6_2016.pdf: General expression for magnetic dipole moment. Magnetic dipole moment associated with electron spin. | hw3 | ||

7 | W 1/27 | day7_2016.pdf: Superimposing the fields from millions of magnetic dipoles. | |||

8 | F 1/29 | day8_2015.pdf: Bound current density, J_b, and bound sheet current, K_b, of magnetized objects. Apply to a solid cylinder and an infinite slab. | hw3soln_2016.pdf | ||

Week5 | Day | Topic | Reading | Summary | Assignments |

9 | M 2/1 | day9_2015.pdf: Linear paramagnetic materials. Linear diamagnetic materials. Using the H-field to find a self-consistent solution for M. | hw4 | ||

10 | W 2/3 | day10_2016.pdf: After finding H, determine M and B. Levitating diamagnetic materials. Frog video. Note about superconductors. Extra material: Quantum mechanical explanation of diamagnetism. | |||

F 2/5 | review for midterm | popquizpacket_day1to10.pdf, practice_question.pdf | hw4soln_2016.pdf | ||

Week6 | Day | Topic | Reading | Summary | Assignments |

M 2/8 | MIDTERM | midterm_winter_2016.pdf | |||

11 | W 2/10 | day11_2016.pdf: Add time-dependent terms to Maxwell's equations. Discuss dB/dt term and the relationship to Faraday's law. The explanation behind Faraday's law depends on reference frame (Lorentz force vs. curlE). Define EMF. | |||

12 | F 2/12 | day12_2016.pdf: Calculating the E-field “generated” by dB/dt. This time-dependent E-field “generates” a small correction to the original B(t) - but we can usually neglect this small correction. Introduce the concept of inductance. | |||

Week7 | Day | Topic | Reading | Summary | Assignments |

13 | M 2/15 | day13_2016.pdf: Calculate inductance of a solenoid. It takes work to get current flowing in a loop. Two expressions for the work done (equivalent to energy stored). Discuss the dE/dt term (displacement current density) in Maxwell's Eqns. | hw5 | ||

14 | W 2/17 | day14_2016.pdf: Time dependent Maxwell equations in matter. Rather than keep track of millions of elementary charges, use P and M. dP/dt is equivalent to a current density. Define displacement current as dD/dt. | |||

15 | F 2/19 | day15_2016.pdf: Electromagnetic plane waves. Looking for general solutions where E and B are self-sustaining in a vacuum. Relationship between k and w. Relationship between E and B. Visualizing plane waves. Phase velocity. | hw5soln_2016.pdf | ||

Week8 | Day | Topic | Reading | Summary | Assignments |

16 | M 2/22 | day16_2016.pdf: EM plane polarization and propagation direction. EM plane waves carry energy. | hw6 | ||

17 | W 2/24 | day17_2016.pdf: EM plane waves in materials. Dispersion relation (first introduction). Definition of refractive index. Frequency dependence of dielectric constant (first introduction). Plane waves at the boundary between 2 materials. Deriving boundary conditions. | |||

18 | F 2/26 | day18_2016.pdf: Fresnel equations. Start with normal incidence. Check that incoming energy flux equals outgoing energy flux. Introduce Fresnel equations for non-zero angle of incidence. Demonstration with a laser pointer and a very full glass of water. | hw6soln_2016.pdf | ||

Week9 | Day | Topic | Reading | Summary | Assignments |

19 | M 3/1 | day19_2016.pdf: Reflectance and Transmittance. R + T = 1. Combined reflectance from two interfaces (without interference effects). Snell's Law. Reflectance vs. angle of incidence. The etymology of s and p polarization. Applications of Brewster's angle. | hw7 | ||

20 | W 3/3 | day20_2016.pdf: The Lorentz Oscillator Model. Explaining the frequency dependence of refractive index in materials. Explaining rainbows. | |||

21 | F 3/5 | day21_2016.pdf: Finish discussion of rainbows. Wave equation inside conducting material. | hw7soln_2016.pdf | ||

Week10 | Day | Topic | Reading | Summary | Assignments |

22 | M 3/8 | day22_2016.pdf: Solution to wave equation inside conducting material. Decaying exponential envelop. Analogy with waves on a tensioned string when damping term is added. Skin depth. Complex index of refraction. | hw8ph632y16c.pdf | ||

23 | W 3/10 | day23_2016.pdf: Refractive index and extinction coefficient. The optical conductivity of “non-conducting” materials - relationship to absorption by quantum mechanical transitions. The frequency-dependent optical conductivity of a free-electron gas (Drude model). | |||

24 | F 3/12 | Review | popquizpack_day11to23.pdf | hw8soln_2016.pdf |

Previous years