Question

Which statement about the phase relation between the electric and magnetic fields in an LC circuit is correct:

a) They are in phase
b) They are out of phase by 90 degrees
c) They are out of phase by 180 degrees
d) They are in antiphase

Answer 1

In an LC circuit, the electric and magnetic fields are out of phase by 90 degrees due to the characteristic phase difference between voltage and current in inductors and capacitors.

Step-by-step explanation:

In an LC circuit, the electric and magnetic fields are out of phase by 90 degrees. This is a characteristic behavior of inductors and capacitors in alternating current (AC) circuits. Specifically, for a pure inductor, the applied voltage leads the current by a quarter cycle or a 90° phase angle. Similarly, for a pure capacitor, the current leads the voltage by 90° in phase. Therefore, when they are combined in an LC circuit, the electric field (associated with the voltage across the capacitor) and the magnetic field (associated with the current in the inductor) end up being out of phase by 90 degrees. This phase difference is crucial for the oscillatory behavior characteristic of LC circuits.