Electromagnetic Waves — Flashcards

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Formula: ∮ B · dl = μ0 I(t) Meaning: The line integral of the magnetic field around a closed loop is equal to μ0 times the current threading the loop. Units: B in tesla, l in metre, I in ampere. Quick…

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A charging capacitor has current in the connecting wires, but between the plates there is no conduction current. Still, a magnetic field exists in the region between the plates. Maxwell resolved this …

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Formula: Id = ε0 (dΦE/dt) Meaning: Displacement current is the current equivalent of the rate of change of electric flux. Units: Id in ampere, ε0 in farad per metre, ΦE in N m²/C. Important point: It …

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Given: Ic = 0.15 A Formula: During charging, Id = Ic Substitution: Id = 0.15 A Answer: The displacement current is 0.15 A.

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When the capacitor is fully charged, no current flows in the connecting wires, so Ic = 0. Also, the electric field between the plates stops changing, so Id = 0. Both currents become zero.

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Formula: ∮ B · dl = μ0 Ic + μ0 ε0 (dΦE/dt) = μ0(Ic + Id) Meaning: The magnetic field around a closed path is produced by both conduction current and displacement current. Units: All current terms are …

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Given: charging current = 0.15 A For a charging capacitor: Id = Ic Substitution: Id = 0.15 A Answer: The displacement current across the plates is 0.15 A.

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Formula: ∮ E · dS = q/ε0 Meaning: The electric flux through a closed surface equals q/ε0, where q is the net enclosed charge. Key point: It is true for both stationary and moving charges.