Which option correctly lists the sequence of cause-and-effect steps that makes an…
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
Which option correctly lists the sequence of cause-and-effect steps that makes an electromagnetic wave self-sustaining in free space?
(a) (i) Constant electric field → conduction current → magnetic field, (ii) Static magnetic field → constant electric field, cycles repeat indefinitely.
(b) (i) Time-varying magnetic field → displacement current → electric field, (ii) Time-varying electric field → conduction current → magnetic field.
(c) (i) Time-varying electric field → displacement current → magnetic field, (ii) Time-varying magnetic field → induced electric field, cycles repeat indefinitely.
(d) (i) Electric field accelerates virtual charges in vacuum → current → magnetic field, (ii) Magnetic field induces e.m.f. that regenerates the current without needing field variation.