Light is defined as a wave of alternating electric and magnetic fields. Which statement best describes light?

Light is defined as a wave of alternating electric and magnetic fields. Which statement best describes light?

• A. A wave of alternating electric and magnetic fields
• B. A stream of energetic particles
• C. A sound wave
• D. A form of matter

Answer: (A)

Light behaves as an electromagnetic wave, meaning its electric and magnetic fields oscillate and propagate through space. This description explains how light travels without a medium and shows why it can be reflected, refracted, and polarised. The idea of a stream of energetic particles would describe matter or particle-like radiation, which isn’t what this wave description captures. A sound wave is a mechanical disturbance in a medium, not an electromagnetic one, and a form of matter implies it has mass, which light does not in the classical sense. So describing light as a wave of alternating electric and magnetic fields best fits how light behaves.

Light behaves as an electromagnetic wave, meaning its electric and magnetic fields oscillate and propagate through space. This description explains how light travels without a medium and shows why it can be reflected, refracted, and polarised. The idea of a stream of energetic particles would describe matter or particle-like radiation, which isn’t what this wave description captures. A sound wave is a mechanical disturbance in a medium, not an electromagnetic one, and a form of matter implies it has mass, which light does not in the classical sense. So describing light as a wave of alternating electric and magnetic fields best fits how light behaves.