Short Answer
The electric and magnetic fields oscillate perpendicular to the direction of propagation is the best answer.
Electromagnetism questions become manageable once you separate source, field, potential, current, and force. Most wrong answers mix those layers together or ignore direction.
EM waves have E and B oscillating perpendicular to each other and to the wave propagation direction.
Why This Answer Is Correct
This is a Medium-level question in Electromagnetism. The prompt is really testing whether you can connect the concept to its defining physical relationship instead of picking a nearby-but-wrong term.
Keep charge, field, potential, and current distinct. That single habit fixes a large fraction of electromagnetism errors.
Choices At A Glance
- A. They travel through a vacuum
- B. The electric and magnetic fields oscillate perpendicular to the direction of propagation
- C. They carry energy
- D. They reflect off conductors
When similar options appear on an exam, eliminate the ones that break the core law, use the wrong units, or confuse a definition with a consequence.
Topic Snapshot
Topic: Electromagnetism
Difficulty: Medium
Best next move: Re-state the governing law in your own words, then solve one more example from the same topic before moving on.