Electromagnetic waves are characterized as which type of wave?

• A. Transverse
• B. Longitudinal
• C. Surface
• D. Sound

Answer: (A)

Electromagnetic waves are transverse because the fields that carry the wave—electric and magnetic fields—oscillate in directions perpendicular to the direction the wave is traveling. The electric and magnetic fields are also perpendicular to each other, forming a right-angle relationship as the wave propagates, and this whole structure can travel through vacuum without a medium.

This stands in contrast to longitudinal waves, where the particles of the medium move back and forth in the same direction as the wave's travel, like sound waves in air. Surface waves occur at boundaries and aren’t defined by the same perpendicular oscillation pattern of E and B fields. Sound, being a mechanical wave, involves pressure changes in a medium and is not an electromagnetic wave.