GENERAL PHYSICS
Learning outcomes of the course unit
Knowledge and understanding:
At the end of this course the student should know the basic phenomena of the classical electromagnetism and the underlying physical laws. Moreover, he should be able to resolve problems on the subjects treated in the theory lectures.
Applying knowledge and understanding:
The student should be able to analyze the electromagnetic phenomena and to interpret them on the basis of the mathematical formulation of the physical laws.
Making judgments:
By the end of the course, the student should be able to understand the physical phenomena of the electromagnetism.
Communication skills:
The student should be able to clearly present the basic concepts of electromagnetism and their consequences on observable phenomena.
Prerequisites
An adequate knowledge of point mass mechanics subject of the General Physics 1 course is required. Although wave propagation is recalled within this course, a background in the kinematics and general properties of waves is desirable too.
Course contents summary
The course program covers the foundations of electrostatics, magnetostatics, and electrodynamics in vacuum, up to electromagnetic waves. The mathematics employed is kept at the most elementary level compatibly with a reasonably complete treatment of the course matter, rather emphasizing the intuition of physical laws. The integral formulation of Maxwell's Equations is therefore coherently followed and differential equations are derived from the corresponding integral ones when needed (e.g. in the case of electromagnetic waves). Lectures on theory are accompanied by an adequate number of classroom exercise sessions, aimed at solving physical problems.
Course contents
Forza elettrostratica: legge di Coulomb. Il campo elettrico. Flusso e circuitazione di un campo vettoriale. Legge di Gauss per campo elettrico. Carattere conservativo del campo elettrostatico: potenziale elettrico. Dipolo elettrico e approssimazione di dipolo. Elettrostatica dei conduttori. Capacità elettrica e condensatori, sistemi di condensatori. Densità di energia del campo elettrico. Materiali dielettrici: polarizzazione e costante dielettrica; origine microscopica della polarizzazione dielettrica. Corrente elettrica ed equazione di continuità per la carica; corrente stazionaria. Leggi di Ohm e resistenza elettrica. Reti di resistori, resistenza equivalente. Circuiti in corrente continua: leggi di Kirchhoff. Definizione di campo magnetico: forza di Lorentz. Moto di cariche in campi magnetici. Forza magnetica su un filo rettilineo percorso da corrente. Magnetostatica nel vuoto: legge di Biot-Savart, legge di Ampere, legge di Gauss per il campo magnetico. Dipolo magnetico, analogia con il corrispettivo elettrico. Magnetostatica nella materia: magnetizzazione, cenni a modelli microscopici per il momento magnetico della materia. Classificazione dei materiali magnetici: diamagnetismo, paramagnetismo e ferromagnetismo. Induzione elettromagnetica: legge di Faraday-Lenz e sue applicazioni, casi riconducibii al moto e alla forza di Lorentz. F.e.m. indotta da campi magnetici variabili: coefficienti di auto- e mutua induzione, trasformatori. Densità di energia del campo magnetico. Oscillatore LC. Corrente alternata: rappresentazione fasoriale di tensione e corrente, impedenza di un circuito; circuiti RC, RL, RLC. Campi elettrici variabili: corrente di spostamento, legge di Ampere-Maxwell. Richiami di cinematica delle onde, equazione delle onde in una dimensione. Le equazioni di Maxwell nel vuoto. Soluzioni di tipo onda piana dalle equazioni di Maxwell. Intensità e quantità di moto delle onde elettromagnetiche, vettore di Poynting. Spettro elettromagnetico.
Electrostatic force, Coulomb's law. Electric field. Flux and circulation of a vector field. Gauss' law for the electric field. Conservative nature of the electrostatic field: electric potential. Electric dipoles and the dipole approximation. Electrostatics of conductors. Electric capacitance and capacitors, capacitor networks. Energy density of the electric field. Dielectric materials: electric polarization and dielectric constant; microscopic mechanisms for the the dielectric polarization. Electric current and continuity equation for charge; steady current. Ohm's laws and electrical resistance. Resistor networks, equivalent resistance. Direct-current circuits: Kirchhoff's laws. Magnetic field definition: Lorentz force. Motion of a charge in a magnetic field. Magnetic force on a straight wire carrying current. Magnetostatics in vacuum: Biot-Savart's law, Ampere's law, Gauss' law for magnetic field. Magnetic dipole, analogy with its electric counterpart. Magnetostatics in materials: magnetization, microscopic models accounting for a resultant magnetic moment in the matter (hints). Classification of magnetic materials: dia-, para-, and ferro-magnetism. Electromagnetic induction: Faraday-Lenz's laws and its applications; cases that can be traced back to motion and Lorentz force. Induced e.m.f. by time-dependent magnetic fields: auto- e mutual induction coefficients, transformers. Energy density of magnetic field. LC oscillating circuit. Alternate current: phasor representation of voltage and current, impedance of a circuit; RC, RL, RLC circuits. Time-dependent electric fields: displacement current, Ampere-Maxwell's law. Kinematics of waves, d'Alembert's wave equation in one dimension (recall). Maxwell's equations in vacuum. Plane-wave solutions of Maxwell's equations. Intensity and momentum of electromagnetic waves, Poynting vector. Electromagnetic spectrum.
Recommended readings
D. Halliday, R. Resnick, J. Walker, Fondamenti di fisica (Elettromagnetismo - Ottica) 7a edizione, Casa Editrice Ambrosiana, Milano, 2015.
Altri testi:
G. Cantatore, L. Vitale, Gettys Fisica 2 (Elettromagnetismo-Onde). McGraw-Hill Libri Italia, Milano, 2011.
Teaching methods
Slides and blackboard exercises.
Assessment methods and criteria
The examination is based on a written test consisting in solving problems and in an an oral exam on theory, which is accessed by students with a minimum classification of 13/30 in the written test. Alternatively, students can participate in two partial written tests during the semester, which warrants access to the oral exam (validity: one year) if a student has got a minimum mark of 13/30 in each one. If however the average classification in the partial test is at least 22/30, the exam is passed without need of an oral test (which can be anyway requested by a student in order to improve his/her classification).
Other informations
Lecture attendance is highly recommended.
