Department of Physical and Chemical Sciences Degree in Physics
Course of “Electromagnetism”
Teacher: Prof. Pasquale Carelli; CFU: 12
________________________________________________________________
Electrification, Coulomb's law, vacuum permittivity. Electric charge: quantization, storage, measurement units, neutrality of matter. Conductors and insulators, superimposition of electrical forces.
Field: Electric field. Electric field generated by a point charge. Representation by means of field lines. Field expression in Cartesian, polar and cylindrical coordinates. Distributions of electric charge on point-likes, lines, surfaces and volumes.
Flow vector fields through open and closed surfaces. Gauss's law in integral form: application to the main symmetrical forms, Gauss's law in differential form. Application of Gauss' law in local form.
Electrical work. Electrostatic potential, measurement units. Work and electrostatic potential energy associated to electrical charges points The electrostatic field as a conservative vector field, the curl operator. Equipotential surfaces and lines of force. Strength of surface charges, electric pressure. Electrostatic energy of interaction between systems of charges. The electric dipole: field and potential, external action on dipoles.
Maxwell's equations for electrostatics. Poisson's and Laplace's equations.
Conductors in electrostatic: Capacity, Coulomb’s theorem. Hollow conductors, electrostatic shield. Capacitors, connection of capacitors, electrostatic energy, pressure electrostatics. Method of image charges.
Dielectrics: Dielectric constant. Polarization. Electric field in a dielectric, dielectric carrier induction. Equations of electrostatics in dielectrics. Charges of polarization. Discontinuity of the fields on the separation surfaces. Electrostatic energy in dielectrics.
Electricity: conduction, current, continuity equation and steady state. Microscopic and macroscopic Ohm's law. Macroscopic and microscopic Joule's law, density of electric power. Connection of resistances. Electromotive force: batteries and generators. The generalized Ohm's law. Kirchhoff's laws for electrical networks. Use of Thévenin's theorem. Charging and discharging capacitors.
Magnetism: Second Laplace equation, Lorentz force, charge dynamic in a magnetic field, action of a magnetic field on coils, the principle of equivalence of Ampère, the Hall’s effect, the magnetic field flux, the divergence of B. The first Laplace equation, the Biot-Savart’s law, the field of a straight wire, actions between circuits carrying currents. Ampère’s law in differential form. Magnetic field of a coil and a solenoid. Magnetic dipole: field and action of the magnetic field on it. Vector potential.
Magnetism of matter: Permeability and magnetic susceptibility. Magnetizing currents. Equations of magneto-static fields H and M. Discontinuity of the fields on the surface of separation. Ferromagnetism.
Electric and magnetic fields that vary over time: Faraday's law and its applications. Principle of conservation of energy and Lenz’s law. Inductance, magnetic energy, magnetic pressure, mutual induction. Combinations of inductors. Inductive transients. Displacement current and Maxwell-Ampère’s law.
Alternating currents: AC circuits, impedance, symbolic method, generator and AC motors.
The waves: general equations, elastic waves, plane waves, Fourier analysis, longitudinal and transverse waves, polarization. Maxwell's equations. Plane electromagnetic waves. Polarization. Poynting’s vector: energy and radiation pressure. Spherical waves. e.m. wave sources. Spectrum of electromagnetic waves. Electromagnetic waves in the media. Speed of light.
Reference text books:
C. Mencuccini – V. Silvestrini , FISICA II Elettromagnetismo – Ottica, Volume II, Liguori ed.
Web text books:
http://it.wikibooks.org/wiki/Fisica_classica
http://it.wikibooks.org/wiki/Esercizi_di_fisica_con_soluzioni
Assessment methods
Each exam session consists of a written and an oral test. The outcome of the written test is valid for the entire session.
During the course some optional written tests will be provided which, if passed, will be valid as written exams. Even students who have not completed their courses in the prescribed time can take advantage of those tests. The exemption applies to all appeals, before the beginning of the new academic year classes.
During all written tests students can keep just a list of formulas and a scientific calculator.
