Sulla scarica di un condensatore ovvero sulla difficoltà di fare modelli giusti

When is radiation important in the discharge of a capacitor? When is it negligible? The answer depends on many geometrical and physical parameters. Reasonable estimates and suitable approximations/schematizations find that the radiated energy is negligible compared to the Joule dissipation unless a small capacitance is used and the circuit is a loop comparable in size to the capacitor. in this case the dominant radiation mode is magnetic dipole. But so doing the lumped model of the circuit ? the only one that allows a relatively easy calculation ? becomes questionable. an important lesson for the teacher is that a too simplistic schematization of a physics problem can lead the students to results that are very far from what happens in the real world.

Numero: Anno XLVII - n.1 - gennaio/marzo 2014

Categoria articolo: Didattica

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