Answer: An electric field (Faraday-Maxwell law).
- A An electric field (Faraday-Maxwell law)
- B Another magnetic field in general practice
- C A gravitational field as frequently described
- D A current in nearby wires mainly in most textbook accounts
Correct answer: A. An electric field (Faraday-Maxwell law)
Explanation: Maxwell extended Faraday's law: a changing magnetic field creates an electric field. Symmetrically, Ampere-Maxwell law: a changing electric field creates a magnetic field. Together, these sustain EM waves.
In an electromagnetic wave, the oscillating electric field (E) and magnetic field (B) are perpendicular to each other and to the direction the wave travels - a purely transverse wave that needs no medium, unlike sound.
Concept context
Maxwell's equations, EM spectrum, properties, and applications of each band.