Giacomo Bonnoli July 26, 2017
Electric charge. Charge quantization, charge conservation. Measurement of the elementary charge: the Millikan’s experiment. Coulomb law. Electric field. Absolute and relative dielectric constant. Field lines. Superimposition principle. Potential energy and electric potential. Field and potential of continuous charge distributions: charged wire, ring, disk and plane. Electric dipole. Electric dipole in an external field. Binding energy for the electron in the hydrogen atom. Flux of the electric field. Gauss theorem and applications to charge distributions with spherical, plane and cilindrical simmetry. Electrostatic induction. Electrostatic shield. Electric capacity. Calculus of capacity for plane, spherica, cilindrical capacitors. Energy in a charged capacitor. Motion of charges in electric field. Applications: cathodic tube. Electrostatics with dielectrics.
Electric current. Drift speed of charge carriers. Conductors and insulants. Elec- tromotive force. Circuits with continuous current. Resistance and resistivity. Ohm laws. Joule effect. Resistors in series and in parallel. Kirchoff’s laws. Volt- meter and amperometer. Wheatstone bridge. Series and parallel of capacitors. Charge and discharge of a capacitor. RC circuits. Characteristic time.
Some simple experimental evidences. Magnetic effect of electric currents. Mag- netic induction and its units. Biot-Savart law. Magnetic permeability in vac- uum. Magnetic force on a wire flown by electric current. Force between two
parallel conductors. Definition of the unit for electric current. Ampere theorem. Magnetic field of an infinite wire, a solenoid and a toroid. Lorentz force. Motion of a charged particle in a magnetic field. Applications: ciclotron, cathodic tube, mass spectrometer. Hall effect. Magnetic dipole momentum. Momentum of the force on a ring flown by electric current, in an uniform magnetic field. Electric engine. Magnetic momentum: orbital, spin. Magnetic properties of the matter: diamagnetism, paramagnetism, ferromagnetism.
Some simple experimental evidences. Faraday’s law. Lenz law. Induced electric field. Induction and energi transfer. Inductance: self and mutual. Alternator. RL circuit in in direct current. Energy in the magnetic field and energy density.
Oscillating circuits: LC and RLC. Resistive, capacitive and inductive load with a generator of alternated current. Inductive and capacitive reactance. Represen- tation of currents and voltages with phase vectors. RLC circuit with alternated current. Forced oscillation and damped oscillations. Impedance and phase of the current. Supplied power and absorbed power . Resonance. Applications: electric engine and alternator. Transformer
Drift current. Gauss law for magnetic fields. Maxwell equations General prop- erties of the waves. Propagation of the electromagnetic wave. Measurements of the speed of light. Poynting vector. Radiative pressure. Polarization. Electro- magnetic spectrum.